From 8686eb38cf7c49de7875bcbb431de5717985376d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20Adel=C3=B6w?= <freben@gmail.com>
Date: Mon, 8 Mar 2021 17:02:51 +0100
Subject: [PATCH] Introduce the `@backstage/errors` package.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Encode thrown errors in the backend as a JSON payload using a facility in that package, and render helpful frontend displays of those errors.

Signed-off-by: Fredrik Adelöw <freben@gmail.com>
---
 .changeset/chilled-kiwis-bathe.md             |   5 +
 .changeset/healthy-cars-do.md                 |  29 ++++
 .changeset/olive-apples-shop.md               |   5 +
 .changeset/silver-weeks-hide.md               |  10 ++
 .changeset/young-suits-sit.md                 |  10 ++
 packages/backend-common/package.json          |   1 +
 packages/backend-common/src/index.ts          |   1 -
 .../src/middleware/errorHandler.test.ts       |  66 +++++++--
 .../src/middleware/errorHandler.ts            |  59 ++++----
 .../src/reading/AzureUrlReader.test.ts        |   2 +-
 .../src/reading/AzureUrlReader.ts             |   2 +-
 .../src/reading/BitbucketUrlReader.test.ts    |   2 +-
 .../src/reading/BitbucketUrlReader.ts         |   2 +-
 .../src/reading/FetchUrlReader.ts             |   2 +-
 .../src/reading/GithubUrlReader.test.ts       |   2 +-
 .../src/reading/GithubUrlReader.ts            |   2 +-
 .../src/reading/GitlabUrlReader.test.ts       |   2 +-
 .../src/reading/GitlabUrlReader.ts            |   2 +-
 .../src/reading/UrlReaderPredicateMux.ts      |   2 +-
 packages/catalog-client/package.json          |   1 +
 packages/catalog-client/src/CatalogClient.ts  |  15 +-
 packages/core/package.json                    |   1 +
 .../CopyTextButton/CopyTextButton.tsx         |  23 +--
 .../ErrorResponse/ErrorResponse.tsx           | 135 ++++++++++++++++++
 .../src/components/ErrorResponse/index.ts     |  17 +++
 packages/core/src/components/index.ts         |   1 +
 packages/create-app/package.json              |   1 +
 packages/create-app/src/lib/versions.ts       |   2 +
 packages/errors/.eslintrc.js                  |   3 +
 packages/errors/CHANGELOG.md                  |   0
 packages/errors/README.md                     |   9 ++
 packages/errors/package.json                  |  42 ++++++
 packages/errors/src/error/CustomErrorBase.ts  |  37 +++++
 .../src/error/common.test.ts}                 |   6 +-
 .../errors.ts => errors/src/error/common.ts}  |  28 +---
 packages/errors/src/error/index.ts            |  25 ++++
 packages/errors/src/error/server.ts           |  43 ++++++
 packages/errors/src/index.ts                  |  18 +++
 .../payload/ServerResponseErrorBody.test.ts   | 135 ++++++++++++++++++
 .../src/payload/ServerResponseErrorBody.ts    |  89 ++++++++++++
 packages/errors/src/payload/index.ts          |  18 +++
 packages/errors/src/setupTests.ts             |  17 +++
 packages/techdocs-common/package.json         |   1 +
 packages/techdocs-common/src/helpers.ts       |   3 +-
 .../src/stages/prepare/commonGit.ts           |   2 +-
 .../techdocs-common/src/stages/prepare/dir.ts |   8 +-
 .../techdocs-common/src/stages/prepare/url.ts |   4 +-
 plugins/auth-backend/package.json             |   1 +
 .../src/lib/catalog/CatalogIdentityClient.ts  |   2 +-
 .../src/lib/oauth/OAuthAdapter.ts             |   2 +-
 .../src/lib/oauth/OAuthEnvironmentHandler.ts  |   2 +-
 plugins/auth-backend/src/service/router.ts    |   2 +-
 plugins/catalog-backend/package.json          |   1 +
 .../src/catalog/DatabaseEntitiesCatalog.ts    |   2 +-
 .../src/database/CommonDatabase.test.ts       |   2 +-
 .../src/database/CommonDatabase.ts            |   6 +-
 .../src/ingestion/LocationReaders.ts          |  60 ++++++--
 .../processors/CodeOwnersProcessor.ts         |   3 +-
 .../src/ingestion/processors/results.ts       |   2 +-
 .../src/service/EntityFilters.ts              |   2 +-
 .../src/service/filterQuery.ts                |   2 +-
 .../src/service/router.test.ts                |   3 +-
 plugins/catalog-backend/src/service/router.ts |  13 +-
 plugins/catalog-backend/src/service/util.ts   |   2 +-
 .../EntityPageLayout/EntityPageLayout.tsx     |   4 +-
 plugins/scaffolder-backend/package.json       |   1 +
 .../src/lib/catalog/CatalogEntityClient.ts    |   2 +-
 .../actions/TemplateActionRegistry.ts         |   2 +-
 .../actions/builtin/catalog/register.ts       |   2 +-
 .../actions/builtin/fetch/cookiecutter.ts     |   3 +-
 .../actions/builtin/fetch/helpers.ts          |   3 +-
 .../scaffolder/actions/builtin/fetch/plain.ts |   3 +-
 .../actions/builtin/publish/azure.ts          |   2 +-
 .../actions/builtin/publish/bitbucket.ts      |   2 +-
 .../actions/builtin/publish/github.ts         |   2 +-
 .../actions/builtin/publish/gitlab.ts         |   2 +-
 .../actions/builtin/publish/util.ts           |   2 +-
 .../src/scaffolder/stages/helpers.ts          |   2 +-
 .../src/scaffolder/stages/prepare/file.ts     |   2 +-
 .../scaffolder/stages/templater/helpers.ts    |   2 +-
 .../src/scaffolder/tasks/DatabaseTaskStore.ts |   7 +-
 .../src/scaffolder/tasks/TaskWorker.ts        |   2 +-
 .../scaffolder-backend/src/service/router.ts  |   8 +-
 plugins/techdocs-backend/package.json         |   1 +
 .../src/DocsBuilder/builder.ts                |   2 +-
 85 files changed, 878 insertions(+), 175 deletions(-)
 create mode 100644 .changeset/chilled-kiwis-bathe.md
 create mode 100644 .changeset/healthy-cars-do.md
 create mode 100644 .changeset/olive-apples-shop.md
 create mode 100644 .changeset/silver-weeks-hide.md
 create mode 100644 .changeset/young-suits-sit.md
 create mode 100644 packages/core/src/components/ErrorResponse/ErrorResponse.tsx
 create mode 100644 packages/core/src/components/ErrorResponse/index.ts
 create mode 100644 packages/errors/.eslintrc.js
 create mode 100644 packages/errors/CHANGELOG.md
 create mode 100644 packages/errors/README.md
 create mode 100644 packages/errors/package.json
 create mode 100644 packages/errors/src/error/CustomErrorBase.ts
 rename packages/{backend-common/src/errors.test.ts => errors/src/error/common.test.ts} (91%)
 rename packages/{backend-common/src/errors.ts => errors/src/error/common.ts} (76%)
 create mode 100644 packages/errors/src/error/index.ts
 create mode 100644 packages/errors/src/error/server.ts
 create mode 100644 packages/errors/src/index.ts
 create mode 100644 packages/errors/src/payload/ServerResponseErrorBody.test.ts
 create mode 100644 packages/errors/src/payload/ServerResponseErrorBody.ts
 create mode 100644 packages/errors/src/payload/index.ts
 create mode 100644 packages/errors/src/setupTests.ts

diff --git a/.changeset/chilled-kiwis-bathe.md b/.changeset/chilled-kiwis-bathe.md
new file mode 100644
index 0000000000000..31e891a8fcd0c
--- /dev/null
+++ b/.changeset/chilled-kiwis-bathe.md
@@ -0,0 +1,5 @@
+---
+'@backstage/catalog-client': patch
+---
+
+Throw the new `ServerResponseError` from `@backstage/errors`
diff --git a/.changeset/healthy-cars-do.md b/.changeset/healthy-cars-do.md
new file mode 100644
index 0000000000000..8de19817093b1
--- /dev/null
+++ b/.changeset/healthy-cars-do.md
@@ -0,0 +1,29 @@
+---
+'@backstage/backend-common': minor
+---
+
+Encode thrown errors in the backend as a JSON payload. This is technically a breaking change, since the response format even of errors are part of the contract. If you relied on the response being text, you will now have some extra JSON "noise" in it. It should still be readable by end users though.
+
+Before:
+
+```
+NotFoundError: No entity named 'tara.macgovern2' found, with kind 'user' in namespace 'default'
+    at eval (webpack-internal:///../../plugins/catalog-backend/src/service/router.ts:117:17)
+```
+
+After:
+
+```json
+{
+  "error": {
+    "statusCode": 404,
+    "name": "NotFoundError",
+    "message": "No entity named 'tara.macgovern2' found, with kind 'user' in namespace 'default'",
+    "stack": "NotFoundError: No entity named 'tara.macgovern2' found, with kind 'user' in namespace 'default'\n    at eval (webpack-internal:///../../plugins/catalog-backend/src/service/router.ts:117:17)"
+  },
+  "request": {
+    "method": "GET",
+    "url": "/entities/by-name/user/default/tara.macgovern2"
+  }
+}
+```
diff --git a/.changeset/olive-apples-shop.md b/.changeset/olive-apples-shop.md
new file mode 100644
index 0000000000000..160f72af5fc3f
--- /dev/null
+++ b/.changeset/olive-apples-shop.md
@@ -0,0 +1,5 @@
+---
+'@backstage/core': patch
+---
+
+Add a `ErrorResponsePanel` to render `ServerResponseError` from `@backstage/errors`
diff --git a/.changeset/silver-weeks-hide.md b/.changeset/silver-weeks-hide.md
new file mode 100644
index 0000000000000..15a75016a293b
--- /dev/null
+++ b/.changeset/silver-weeks-hide.md
@@ -0,0 +1,10 @@
+---
+'@backstage/techdocs-common': patch
+'@backstage/plugin-auth-backend': patch
+'@backstage/plugin-catalog': patch
+'@backstage/plugin-catalog-backend': patch
+'@backstage/plugin-scaffolder-backend': patch
+'@backstage/plugin-techdocs-backend': patch
+---
+
+Use errors from `@backstage/errors`
diff --git a/.changeset/young-suits-sit.md b/.changeset/young-suits-sit.md
new file mode 100644
index 0000000000000..5728c52ef8809
--- /dev/null
+++ b/.changeset/young-suits-sit.md
@@ -0,0 +1,10 @@
+---
+'@backstage/backend-common': minor
+---
+
+Removed the custom error types (e.g. `NotFoundError`). Those are now instead in the new `@backstage/errors` package. This is a breaking change, and you will have to update your imports if you were using these types.
+
+```diff
+-import { NotFoundError } from '@backstage/backend-common';
++import { NotFoundError } from '@backstage/errors';
+```
diff --git a/packages/backend-common/package.json b/packages/backend-common/package.json
index 43b5114de455b..933d2ccb3a3d9 100644
--- a/packages/backend-common/package.json
+++ b/packages/backend-common/package.json
@@ -32,6 +32,7 @@
     "@backstage/cli-common": "^0.1.1",
     "@backstage/config": "^0.1.2",
     "@backstage/config-loader": "^0.5.1",
+    "@backstage/errors": "^0.1.1",
     "@backstage/integration": "^0.5.1",
     "@octokit/rest": "^18.0.12",
     "@types/cors": "^2.8.6",
diff --git a/packages/backend-common/src/index.ts b/packages/backend-common/src/index.ts
index f3653f2627573..29b1062750c47 100644
--- a/packages/backend-common/src/index.ts
+++ b/packages/backend-common/src/index.ts
@@ -17,7 +17,6 @@
 export * from './config';
 export * from './database';
 export * from './discovery';
-export * from './errors';
 export * from './hot';
 export * from './logging';
 export * from './middleware';
diff --git a/packages/backend-common/src/middleware/errorHandler.test.ts b/packages/backend-common/src/middleware/errorHandler.test.ts
index 78baaf5090afe..50af586686bed 100644
--- a/packages/backend-common/src/middleware/errorHandler.test.ts
+++ b/packages/backend-common/src/middleware/errorHandler.test.ts
@@ -14,10 +14,17 @@
  * limitations under the License.
  */
 
+import {
+  AuthenticationError,
+  ConflictError,
+  InputError,
+  NotAllowedError,
+  NotFoundError,
+  NotModifiedError,
+} from '@backstage/errors';
 import express from 'express';
 import createError from 'http-errors';
 import request from 'supertest';
-import * as errors from '../errors';
 import { errorHandler } from './errorHandler';
 
 describe('errorHandler', () => {
@@ -31,17 +38,27 @@ describe('errorHandler', () => {
     const response = await request(app).get('/breaks');
 
     expect(response.status).toBe(500);
-    expect(response.text).toBe('some message');
+    expect(response.body).toEqual({
+      error: {
+        statusCode: 500,
+        name: 'Error',
+        message: 'some message',
+      },
+      request: {
+        method: 'GET',
+        url: '/breaks',
+      },
+    });
   });
 
-  it('doesnt try to send the response again if its already been sent', async () => {
+  it('does not try to send the response again if its already been sent', async () => {
     const app = express();
     const mockSend = jest.fn();
 
     app.use('/works_with_async_fail', (_, res) => {
       res.status(200).send('hello');
 
-      // mutate the response object to test the middlware.
+      // mutate the response object to test the middleware.
       // it's hard to catch errors inside middleware from the outside.
       // @ts-ignore
       res.send = mockSend;
@@ -67,38 +84,61 @@ describe('errorHandler', () => {
     const response = await request(app).get('/breaks');
 
     expect(response.status).toBe(432);
-    expect(response.text).toContain('Some Message');
+    expect(response.body).toEqual({
+      error: {
+        statusCode: 432,
+        name: 'BadRequestError',
+        message: 'Some Message',
+      },
+      request: {
+        method: 'GET',
+        url: '/breaks',
+      },
+    });
   });
 
   it('handles well-known error classes', async () => {
     const app = express();
     app.use('/NotModifiedError', () => {
-      throw new errors.NotModifiedError();
+      throw new NotModifiedError();
     });
     app.use('/InputError', () => {
-      throw new errors.InputError();
+      throw new InputError();
     });
     app.use('/AuthenticationError', () => {
-      throw new errors.AuthenticationError();
+      throw new AuthenticationError();
     });
     app.use('/NotAllowedError', () => {
-      throw new errors.NotAllowedError();
+      throw new NotAllowedError();
     });
     app.use('/NotFoundError', () => {
-      throw new errors.NotFoundError();
+      throw new NotFoundError();
     });
     app.use('/ConflictError', () => {
-      throw new errors.ConflictError();
+      throw new ConflictError();
     });
     app.use(errorHandler());
 
     const r = request(app);
     expect((await r.get('/NotModifiedError')).status).toBe(304);
     expect((await r.get('/InputError')).status).toBe(400);
+    expect((await r.get('/InputError')).body.error.name).toBe('InputError');
     expect((await r.get('/AuthenticationError')).status).toBe(401);
+    expect((await r.get('/AuthenticationError')).body.error.name).toBe(
+      'AuthenticationError',
+    );
     expect((await r.get('/NotAllowedError')).status).toBe(403);
+    expect((await r.get('/NotAllowedError')).body.error.name).toBe(
+      'NotAllowedError',
+    );
     expect((await r.get('/NotFoundError')).status).toBe(404);
+    expect((await r.get('/NotFoundError')).body.error.name).toBe(
+      'NotFoundError',
+    );
     expect((await r.get('/ConflictError')).status).toBe(409);
+    expect((await r.get('/ConflictError')).body.error.name).toBe(
+      'ConflictError',
+    );
   });
 
   it('logs all 500 errors', async () => {
@@ -126,7 +166,7 @@ describe('errorHandler', () => {
     mockLogger.child.mockImplementation(() => mockLogger as any);
 
     app.use('/NotFound', () => {
-      throw new errors.NotFoundError();
+      throw new NotFoundError();
     });
     app.use(errorHandler({ logger: mockLogger as any }));
 
@@ -142,7 +182,7 @@ describe('errorHandler', () => {
     mockLogger.child.mockImplementation(() => mockLogger as any);
 
     app.use('/NotFound', () => {
-      throw new errors.NotFoundError();
+      throw new NotFoundError();
     });
     app.use(errorHandler({ logger: mockLogger as any, logClientErrors: true }));
 
diff --git a/packages/backend-common/src/middleware/errorHandler.ts b/packages/backend-common/src/middleware/errorHandler.ts
index 4b609a649f469..4dc6d4c85f9c8 100644
--- a/packages/backend-common/src/middleware/errorHandler.ts
+++ b/packages/backend-common/src/middleware/errorHandler.ts
@@ -16,7 +16,15 @@
 
 import { ErrorRequestHandler, NextFunction, Request, Response } from 'express';
 import { Logger } from 'winston';
-import * as errors from '../errors';
+import {
+  NotModifiedError,
+  InputError,
+  AuthenticationError,
+  NotAllowedError,
+  NotFoundError,
+  ConflictError,
+  ServerResponseErrorBody,
+} from '@backstage/errors';
 import { getRootLogger } from '../logging';
 
 export type ErrorHandlerOptions = {
@@ -48,14 +56,13 @@ export type ErrorHandlerOptions = {
  * This is commonly the very last middleware in the chain.
  *
  * Its primary purpose is not to do translation of business logic exceptions,
- * but rather to be a gobal catch-all for uncaught "fatal" errors that are
+ * but rather to be a global catch-all for uncaught "fatal" errors that are
  * expected to result in a 500 error. However, it also does handle some common
  * error types (such as http-error exceptions) and returns the enclosed status
  * code accordingly.
  *
  * @returns An Express error request handler
  */
-
 export function errorHandler(
   options: ErrorHandlerOptions = {},
 ): ErrorRequestHandler {
@@ -66,12 +73,12 @@ export function errorHandler(
     type: 'errorHandler',
   });
 
-  return (
-    error: Error,
-    _request: Request,
-    res: Response,
-    next: NextFunction,
-  ) => {
+  return (error: Error, req: Request, res: Response, next: NextFunction) => {
+    const statusCode = getStatusCode(error);
+    if (options.logClientErrors || statusCode >= 500) {
+      logger.error(error);
+    }
+
     if (res.headersSent) {
       // If the headers have already been sent, do not send the response again
       // as this will throw an error in the backend.
@@ -79,16 +86,20 @@ export function errorHandler(
       return;
     }
 
-    const status = getStatusCode(error);
-    const message = showStackTraces ? error.stack : error.message;
-
-    if (options.logClientErrors || status >= 500) {
-      logger.error(error);
-    }
+    const body: ServerResponseErrorBody = {
+      error: {
+        statusCode,
+        name: error.name || 'Error',
+        message: error.message || '<no reason given>',
+        stack: showStackTraces ? error.stack : undefined,
+      },
+      request: {
+        method: req.method,
+        url: req.url,
+      },
+    };
 
-    res.status(status);
-    res.setHeader('content-type', 'text/plain');
-    res.send(message);
+    res.status(statusCode).json(body);
   };
 }
 
@@ -109,17 +120,17 @@ function getStatusCode(error: Error): number {
 
   // Handle well-known error types
   switch (error.name) {
-    case errors.NotModifiedError.name:
+    case NotModifiedError.name:
       return 304;
-    case errors.InputError.name:
+    case InputError.name:
       return 400;
-    case errors.AuthenticationError.name:
+    case AuthenticationError.name:
       return 401;
-    case errors.NotAllowedError.name:
+    case NotAllowedError.name:
       return 403;
-    case errors.NotFoundError.name:
+    case NotFoundError.name:
       return 404;
-    case errors.ConflictError.name:
+    case ConflictError.name:
       return 409;
     default:
       break;
diff --git a/packages/backend-common/src/reading/AzureUrlReader.test.ts b/packages/backend-common/src/reading/AzureUrlReader.test.ts
index b52097baf55c0..bb761812876e7 100644
--- a/packages/backend-common/src/reading/AzureUrlReader.test.ts
+++ b/packages/backend-common/src/reading/AzureUrlReader.test.ts
@@ -26,7 +26,7 @@ import { rest } from 'msw';
 import { setupServer } from 'msw/node';
 import * as os from 'os';
 import path from 'path';
-import { NotModifiedError } from '../errors';
+import { NotModifiedError } from '@backstage/errors';
 import { getVoidLogger } from '../logging';
 import { AzureUrlReader } from './AzureUrlReader';
 import { ReadTreeResponseFactory } from './tree';
diff --git a/packages/backend-common/src/reading/AzureUrlReader.ts b/packages/backend-common/src/reading/AzureUrlReader.ts
index 21b988e5b07ed..16e7628ec8406 100644
--- a/packages/backend-common/src/reading/AzureUrlReader.ts
+++ b/packages/backend-common/src/reading/AzureUrlReader.ts
@@ -26,7 +26,7 @@ import fetch from 'cross-fetch';
 import parseGitUrl from 'git-url-parse';
 import { Minimatch } from 'minimatch';
 import { Readable } from 'stream';
-import { NotFoundError, NotModifiedError } from '../errors';
+import { NotFoundError, NotModifiedError } from '@backstage/errors';
 import { ReadTreeResponseFactory } from './tree';
 import { stripFirstDirectoryFromPath } from './tree/util';
 import {
diff --git a/packages/backend-common/src/reading/BitbucketUrlReader.test.ts b/packages/backend-common/src/reading/BitbucketUrlReader.test.ts
index df9febb352add..aa78bf27d5bac 100644
--- a/packages/backend-common/src/reading/BitbucketUrlReader.test.ts
+++ b/packages/backend-common/src/reading/BitbucketUrlReader.test.ts
@@ -26,7 +26,7 @@ import { rest } from 'msw';
 import { setupServer } from 'msw/node';
 import os from 'os';
 import path from 'path';
-import { NotModifiedError } from '../errors';
+import { NotModifiedError } from '@backstage/errors';
 import { BitbucketUrlReader } from './BitbucketUrlReader';
 import { ReadTreeResponseFactory } from './tree';
 
diff --git a/packages/backend-common/src/reading/BitbucketUrlReader.ts b/packages/backend-common/src/reading/BitbucketUrlReader.ts
index 3954e7ee4a47a..f102be7283730 100644
--- a/packages/backend-common/src/reading/BitbucketUrlReader.ts
+++ b/packages/backend-common/src/reading/BitbucketUrlReader.ts
@@ -26,7 +26,7 @@ import fetch from 'cross-fetch';
 import parseGitUrl from 'git-url-parse';
 import { Minimatch } from 'minimatch';
 import { Readable } from 'stream';
-import { NotFoundError, NotModifiedError } from '../errors';
+import { NotFoundError, NotModifiedError } from '@backstage/errors';
 import { ReadTreeResponseFactory } from './tree';
 import { stripFirstDirectoryFromPath } from './tree/util';
 import {
diff --git a/packages/backend-common/src/reading/FetchUrlReader.ts b/packages/backend-common/src/reading/FetchUrlReader.ts
index 0b26dfe911c43..57bab5e58d86b 100644
--- a/packages/backend-common/src/reading/FetchUrlReader.ts
+++ b/packages/backend-common/src/reading/FetchUrlReader.ts
@@ -15,7 +15,7 @@
  */
 
 import fetch from 'cross-fetch';
-import { NotFoundError } from '../errors';
+import { NotFoundError } from '@backstage/errors';
 import {
   ReaderFactory,
   ReadTreeResponse,
diff --git a/packages/backend-common/src/reading/GithubUrlReader.test.ts b/packages/backend-common/src/reading/GithubUrlReader.test.ts
index 94e4d0fd315ce..67e7f27069093 100644
--- a/packages/backend-common/src/reading/GithubUrlReader.test.ts
+++ b/packages/backend-common/src/reading/GithubUrlReader.test.ts
@@ -27,7 +27,7 @@ import { rest } from 'msw';
 import { setupServer } from 'msw/node';
 import os from 'os';
 import path from 'path';
-import { NotFoundError, NotModifiedError } from '../errors';
+import { NotFoundError, NotModifiedError } from '@backstage/errors';
 import {
   GhBlobResponse,
   GhBranchResponse,
diff --git a/packages/backend-common/src/reading/GithubUrlReader.ts b/packages/backend-common/src/reading/GithubUrlReader.ts
index ac5a93bd5fb8e..77e33cbd541eb 100644
--- a/packages/backend-common/src/reading/GithubUrlReader.ts
+++ b/packages/backend-common/src/reading/GithubUrlReader.ts
@@ -25,7 +25,7 @@ import fetch from 'cross-fetch';
 import parseGitUrl from 'git-url-parse';
 import { Minimatch } from 'minimatch';
 import { Readable } from 'stream';
-import { NotFoundError, NotModifiedError } from '../errors';
+import { NotFoundError, NotModifiedError } from '@backstage/errors';
 import { ReadTreeResponseFactory } from './tree';
 import {
   ReaderFactory,
diff --git a/packages/backend-common/src/reading/GitlabUrlReader.test.ts b/packages/backend-common/src/reading/GitlabUrlReader.test.ts
index 636540caa816b..9dcc92a4a6355 100644
--- a/packages/backend-common/src/reading/GitlabUrlReader.test.ts
+++ b/packages/backend-common/src/reading/GitlabUrlReader.test.ts
@@ -25,7 +25,7 @@ import path from 'path';
 import { getVoidLogger } from '../logging';
 import { GitlabUrlReader } from './GitlabUrlReader';
 import { ReadTreeResponseFactory } from './tree';
-import { NotModifiedError, NotFoundError } from '../errors';
+import { NotModifiedError, NotFoundError } from '@backstage/errors';
 import {
   GitLabIntegration,
   readGitLabIntegrationConfig,
diff --git a/packages/backend-common/src/reading/GitlabUrlReader.ts b/packages/backend-common/src/reading/GitlabUrlReader.ts
index 66ceae05c6556..c93103b2da2f5 100644
--- a/packages/backend-common/src/reading/GitlabUrlReader.ts
+++ b/packages/backend-common/src/reading/GitlabUrlReader.ts
@@ -24,7 +24,7 @@ import fetch from 'cross-fetch';
 import parseGitUrl from 'git-url-parse';
 import { Minimatch } from 'minimatch';
 import { Readable } from 'stream';
-import { NotFoundError, NotModifiedError } from '../errors';
+import { NotFoundError, NotModifiedError } from '@backstage/errors';
 import { ReadTreeResponseFactory } from './tree';
 import { stripFirstDirectoryFromPath } from './tree/util';
 import {
diff --git a/packages/backend-common/src/reading/UrlReaderPredicateMux.ts b/packages/backend-common/src/reading/UrlReaderPredicateMux.ts
index 91f4ae63ab36a..06ca0c5971b8f 100644
--- a/packages/backend-common/src/reading/UrlReaderPredicateMux.ts
+++ b/packages/backend-common/src/reading/UrlReaderPredicateMux.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { NotAllowedError } from '../errors';
+import { NotAllowedError } from '@backstage/errors';
 import {
   ReadTreeOptions,
   ReadTreeResponse,
diff --git a/packages/catalog-client/package.json b/packages/catalog-client/package.json
index 9115a29ab36c6..36d63a42304a2 100644
--- a/packages/catalog-client/package.json
+++ b/packages/catalog-client/package.json
@@ -31,6 +31,7 @@
   "dependencies": {
     "@backstage/catalog-model": "^0.7.4",
     "@backstage/config": "^0.1.2",
+    "@backstage/errors": "^0.1.1",
     "cross-fetch": "^3.0.6"
   },
   "devDependencies": {
diff --git a/packages/catalog-client/src/CatalogClient.ts b/packages/catalog-client/src/CatalogClient.ts
index a1af0240f6487..2d9a07a7a801e 100644
--- a/packages/catalog-client/src/CatalogClient.ts
+++ b/packages/catalog-client/src/CatalogClient.ts
@@ -21,6 +21,7 @@ import {
   LOCATION_ANNOTATION,
   stringifyLocationReference,
 } from '@backstage/catalog-model';
+import { ServerResponseError } from '@backstage/errors';
 import fetch from 'cross-fetch';
 import {
   AddLocationRequest,
@@ -153,10 +154,7 @@ export class CatalogClient implements CatalogApi {
       },
     );
     if (!response.ok) {
-      const payload = await response.text();
-      throw new Error(
-        `Request failed with ${response.status} ${response.statusText}, ${payload}`,
-      );
+      throw await ServerResponseError.forResponse(response);
     }
     return undefined;
   }
@@ -177,9 +175,7 @@ export class CatalogClient implements CatalogApi {
     });
 
     if (!response.ok) {
-      const payload = await response.text();
-      const message = `Request failed with ${response.status} ${response.statusText}, ${payload}`;
-      throw new Error(message);
+      throw await ServerResponseError.forResponse(response);
     }
 
     return await response.json();
@@ -200,10 +196,7 @@ export class CatalogClient implements CatalogApi {
       if (response.status === 404) {
         return undefined;
       }
-
-      const payload = await response.text();
-      const message = `Request failed with ${response.status} ${response.statusText}, ${payload}`;
-      throw new Error(message);
+      throw await ServerResponseError.forResponse(response);
     }
 
     return await response.json();
diff --git a/packages/core/package.json b/packages/core/package.json
index 6eda51100fc52..4a95fe63e28d3 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -31,6 +31,7 @@
   "dependencies": {
     "@backstage/config": "^0.1.3",
     "@backstage/core-api": "^0.2.13",
+    "@backstage/errors": "^0.1.1",
     "@backstage/theme": "^0.2.4",
     "@material-ui/core": "^4.11.0",
     "@material-ui/icons": "^4.9.1",
diff --git a/packages/core/src/components/CopyTextButton/CopyTextButton.tsx b/packages/core/src/components/CopyTextButton/CopyTextButton.tsx
index 9f6cdd7e7cc08..7f20aed496f60 100644
--- a/packages/core/src/components/CopyTextButton/CopyTextButton.tsx
+++ b/packages/core/src/components/CopyTextButton/CopyTextButton.tsx
@@ -14,21 +14,11 @@
  * limitations under the License.
  */
 
-import React, { useRef, useState, MouseEventHandler } from 'react';
-import { IconButton, makeStyles, Tooltip } from '@material-ui/core';
-import PropTypes from 'prop-types';
-import CopyIcon from '@material-ui/icons/FileCopy';
-import { BackstageTheme } from '@backstage/theme';
 import { errorApiRef, useApi } from '@backstage/core-api';
-
-const useStyles = makeStyles<BackstageTheme>(theme => ({
-  button: {
-    '&:hover': {
-      backgroundColor: theme.palette.highlight,
-      cursor: 'pointer',
-    },
-  },
-}));
+import { IconButton, Tooltip } from '@material-ui/core';
+import CopyIcon from '@material-ui/icons/FileCopy';
+import PropTypes from 'prop-types';
+import React, { MouseEventHandler, useRef, useState } from 'react';
 
 /**
  * Copy text button with visual feedback in the form of
@@ -61,7 +51,6 @@ export const CopyTextButton = (props: Props) => {
     ...defaultProps,
     ...props,
   };
-  const classes = useStyles(props);
   const errorApi = useApi(errorApiRef);
   const inputRef = useRef<HTMLTextAreaElement>(null);
   const [open, setOpen] = useState(false);
@@ -84,7 +73,7 @@ export const CopyTextButton = (props: Props) => {
     <>
       <textarea
         ref={inputRef}
-        style={{ position: 'absolute', top: -9999, left: 9999 }}
+        style={{ position: 'absolute', top: -9999, left: -9999 }}
         defaultValue={text}
       />
       <Tooltip
@@ -95,7 +84,7 @@ export const CopyTextButton = (props: Props) => {
         onClose={() => setOpen(false)}
         open={open}
       >
-        <IconButton onClick={handleCopyClick} className={classes.button}>
+        <IconButton onClick={handleCopyClick}>
           <CopyIcon />
         </IconButton>
       </Tooltip>
diff --git a/packages/core/src/components/ErrorResponse/ErrorResponse.tsx b/packages/core/src/components/ErrorResponse/ErrorResponse.tsx
new file mode 100644
index 0000000000000..2a3c193d6b6bb
--- /dev/null
+++ b/packages/core/src/components/ErrorResponse/ErrorResponse.tsx
@@ -0,0 +1,135 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { ServerResponseError } from '@backstage/errors';
+import {
+  Divider,
+  List,
+  ListItem,
+  ListItemText,
+  makeStyles,
+} from '@material-ui/core';
+import React from 'react';
+import { CodeSnippet } from '../CodeSnippet';
+import { CopyTextButton } from '../CopyTextButton';
+import { WarningPanel } from '../WarningPanel';
+
+const useStyles = makeStyles(theme => ({
+  text: {
+    fontFamily: 'monospace',
+    whiteSpace: 'pre',
+    overflowX: 'auto',
+    marginRight: theme.spacing(2),
+  },
+  divider: {
+    margin: theme.spacing(2),
+  },
+}));
+
+type Props = {
+  error: Error;
+};
+
+/**
+ * Renders details about a failed server request.
+ *
+ * Has special treatment for ServerResponseError errors, to display rich
+ * server-provided information about what happened.
+ */
+export const ErrorResponse = ({ error }: Props) => {
+  const classes = useStyles();
+
+  if (error.name !== 'ServerResponseError') {
+    return (
+      <List>
+        <ListItemText primary="Message" secondary={error.message} />
+      </List>
+    );
+  }
+
+  const { body } = error as ServerResponseError;
+  const errorString = `${body.error.statusCode}: ${body.error.name}`;
+  const request = body.request && `${body.request.method} ${body.request.url}`;
+  const message = body.error.message.replace(/\\n/g, '\n');
+  const stack = body.error.stack?.replace(/\\n/g, '\n');
+  const json = JSON.stringify(error, undefined, 2);
+
+  return (
+    <>
+      <List dense>
+        <ListItem alignItems="flex-start">
+          <ListItemText
+            classes={{ secondary: classes.text }}
+            primary="Error"
+            secondary={errorString}
+          />
+          <CopyTextButton text={errorString} />
+        </ListItem>
+        <ListItem alignItems="flex-start">
+          <ListItemText
+            classes={{ secondary: classes.text }}
+            primary="Message"
+            secondary={message}
+          />
+          <CopyTextButton text={message} />
+        </ListItem>
+        {request ? (
+          <ListItem alignItems="flex-start">
+            <ListItemText
+              classes={{ secondary: classes.text }}
+              primary="Request"
+              secondary={request}
+            />
+            <CopyTextButton text={request} />
+          </ListItem>
+        ) : null}
+        {stack ? (
+          <ListItem alignItems="flex-start">
+            <ListItemText
+              classes={{ secondary: classes.text }}
+              primary="Stack Trace"
+              secondary={stack}
+            />
+            <CopyTextButton text={stack} />
+          </ListItem>
+        ) : null}
+        <Divider component="li" className={classes.divider} />
+        <ListItem alignItems="flex-start">
+          <ListItemText
+            classes={{ secondary: classes.text }}
+            primary="Full Error as JSON"
+            secondary={<CodeSnippet language="json" text={json} />}
+          />
+          <CopyTextButton text={json} />
+        </ListItem>
+      </List>
+    </>
+  );
+};
+
+/**
+ * Renders a warning panel as the effect of a failed server request.
+ *
+ * Has special treatment for ServerResponseError errors, to display rich
+ * server-provided information about what happened.
+ */
+export const ErrorResponsePanel = ({ error }: Props) => {
+  return (
+    <WarningPanel title={error.message}>
+      <ErrorResponse error={error} />
+    </WarningPanel>
+  );
+};
diff --git a/packages/core/src/components/ErrorResponse/index.ts b/packages/core/src/components/ErrorResponse/index.ts
new file mode 100644
index 0000000000000..24463ddb3789b
--- /dev/null
+++ b/packages/core/src/components/ErrorResponse/index.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export { ErrorResponse, ErrorResponsePanel } from './ErrorResponse';
diff --git a/packages/core/src/components/index.ts b/packages/core/src/components/index.ts
index 58d0a8f5697c6..35cd4e5b2e8b4 100644
--- a/packages/core/src/components/index.ts
+++ b/packages/core/src/components/index.ts
@@ -22,6 +22,7 @@ export * from './CopyTextButton';
 export * from './DependencyGraph';
 export * from './DismissableBanner';
 export * from './EmptyState';
+export * from './ErrorResponse';
 export * from './FeatureDiscovery';
 export * from './HeaderIconLinkRow';
 export * from './HorizontalScrollGrid';
diff --git a/packages/create-app/package.json b/packages/create-app/package.json
index e04e5bae1243f..9016ce9563401 100644
--- a/packages/create-app/package.json
+++ b/packages/create-app/package.json
@@ -50,6 +50,7 @@
     "@backstage/cli": "*",
     "@backstage/config": "*",
     "@backstage/core": "*",
+    "@backstage/errors": "*",
     "@backstage/plugin-api-docs": "*",
     "@backstage/plugin-app-backend": "*",
     "@backstage/plugin-auth-backend": "*",
diff --git a/packages/create-app/src/lib/versions.ts b/packages/create-app/src/lib/versions.ts
index 9a05a95ac020d..32a87bb323a65 100644
--- a/packages/create-app/src/lib/versions.ts
+++ b/packages/create-app/src/lib/versions.ts
@@ -36,6 +36,7 @@ import { version as catalogModel } from '../../../catalog-model/package.json';
 import { version as cli } from '../../../cli/package.json';
 import { version as config } from '../../../config/package.json';
 import { version as core } from '../../../core/package.json';
+import { version as errors } from '../../../errors/package.json';
 import { version as testUtils } from '../../../test-utils/package.json';
 import { version as theme } from '../../../theme/package.json';
 
@@ -67,6 +68,7 @@ export const packageVersions = {
   '@backstage/cli': cli,
   '@backstage/config': config,
   '@backstage/core': core,
+  '@backstage/errors': errors,
   '@backstage/plugin-api-docs': pluginApiDocs,
   '@backstage/plugin-app-backend': pluginAppBackend,
   '@backstage/plugin-auth-backend': pluginAuthBackend,
diff --git a/packages/errors/.eslintrc.js b/packages/errors/.eslintrc.js
new file mode 100644
index 0000000000000..13573efa9c466
--- /dev/null
+++ b/packages/errors/.eslintrc.js
@@ -0,0 +1,3 @@
+module.exports = {
+  extends: [require.resolve('@backstage/cli/config/eslint')],
+};
diff --git a/packages/errors/CHANGELOG.md b/packages/errors/CHANGELOG.md
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/packages/errors/README.md b/packages/errors/README.md
new file mode 100644
index 0000000000000..8018e89980e8a
--- /dev/null
+++ b/packages/errors/README.md
@@ -0,0 +1,9 @@
+# Common error handling functionality
+
+Contains some common functionality of error handling.
+
+This package will be imported both by the frontend and backend.
+
+## Links
+
+- [The Backstage homepage](https://backstage.io)
diff --git a/packages/errors/package.json b/packages/errors/package.json
new file mode 100644
index 0000000000000..cbc7098cb3e91
--- /dev/null
+++ b/packages/errors/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "@backstage/errors",
+  "version": "0.1.1",
+  "main": "src/index.ts",
+  "types": "src/index.ts",
+  "license": "Apache-2.0",
+  "private": false,
+  "publishConfig": {
+    "access": "public",
+    "main": "dist/index.cjs.js",
+    "module": "dist/index.esm.js",
+    "types": "dist/index.d.ts"
+  },
+  "homepage": "https://backstage.io",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/backstage/backstage",
+    "directory": "packages/errors"
+  },
+  "keywords": [
+    "backstage"
+  ],
+  "scripts": {
+    "build": "backstage-cli build",
+    "lint": "backstage-cli lint",
+    "test": "backstage-cli test",
+    "prepack": "backstage-cli prepack",
+    "postpack": "backstage-cli postpack",
+    "clean": "backstage-cli clean"
+  },
+  "dependencies": {
+    "@backstage/config": "^0.1.2",
+    "cross-fetch": "^3.0.6"
+  },
+  "devDependencies": {
+    "@backstage/cli": "^0.6.1",
+    "@types/jest": "^26.0.7"
+  },
+  "files": [
+    "dist"
+  ]
+}
diff --git a/packages/errors/src/error/CustomErrorBase.ts b/packages/errors/src/error/CustomErrorBase.ts
new file mode 100644
index 0000000000000..cd28d4cda3447
--- /dev/null
+++ b/packages/errors/src/error/CustomErrorBase.ts
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export class CustomErrorBase extends Error {
+  readonly cause?: Error;
+
+  constructor(message?: string, cause?: Error) {
+    let fullMessage = message;
+    if (cause) {
+      if (fullMessage) {
+        fullMessage += `; caused by ${cause}`;
+      } else {
+        fullMessage = `caused by ${cause}`;
+      }
+    }
+
+    super(fullMessage);
+
+    Error.captureStackTrace?.(this, this.constructor);
+
+    this.name = this.constructor.name;
+    this.cause = cause;
+  }
+}
diff --git a/packages/backend-common/src/errors.test.ts b/packages/errors/src/error/common.test.ts
similarity index 91%
rename from packages/backend-common/src/errors.test.ts
rename to packages/errors/src/error/common.test.ts
index ecff8764c089e..97e616c718c93 100644
--- a/packages/backend-common/src/errors.test.ts
+++ b/packages/errors/src/error/common.test.ts
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-import * as errors from './errors';
+import * as errors from './common';
 
-describe('errors', () => {
+describe('common', () => {
   it('extends Error properly', () => {
     for (const [name, E] of Object.entries(errors)) {
       const error = new E('abcdef');
@@ -30,7 +30,7 @@ describe('errors', () => {
 
   it('supports causes', () => {
     const cause = new Error('hello');
-    for (const [, E] of Object.entries(errors)) {
+    for (const [name, E] of Object.entries(errors)) {
       const error = new E('abcdef', cause);
       expect(error.cause).toBe(cause);
       expect(error.toString()).toContain(
diff --git a/packages/backend-common/src/errors.ts b/packages/errors/src/error/common.ts
similarity index 76%
rename from packages/backend-common/src/errors.ts
rename to packages/errors/src/error/common.ts
index 39703127e65de..60fa540355c70 100644
--- a/packages/backend-common/src/errors.ts
+++ b/packages/errors/src/error/common.ts
@@ -14,39 +14,19 @@
  * limitations under the License.
  */
 
+import { CustomErrorBase } from './CustomErrorBase';
+
 /*
  * A set of common business logic errors.
  *
- * The error handler middleware understands these and will translate them to
- * well formed HTTP responses.
+ * A backend error handler middleware would understand these and translate them
+ * to well formed HTTP responses.
  *
  * While these are intentionally analogous to HTTP errors, they are not
  * intended to be thrown by the request handling layer. In those places, please
  * use e.g. the http-errors library.
  */
 
-class CustomErrorBase extends Error {
-  readonly cause?: Error;
-
-  constructor(message?: string, cause?: Error) {
-    let fullMessage = message;
-    if (cause) {
-      if (fullMessage) {
-        fullMessage += `; caused by ${cause}`;
-      } else {
-        fullMessage = `caused by ${cause}`;
-      }
-    }
-
-    super(fullMessage);
-
-    Error.captureStackTrace(this, this.constructor);
-
-    this.name = this.constructor.name;
-    this.cause = cause;
-  }
-}
-
 /**
  * The given inputs are malformed and cannot be processed.
  */
diff --git a/packages/errors/src/error/index.ts b/packages/errors/src/error/index.ts
new file mode 100644
index 0000000000000..4fcac24004573
--- /dev/null
+++ b/packages/errors/src/error/index.ts
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export {
+  InputError,
+  AuthenticationError,
+  NotAllowedError,
+  NotFoundError,
+  ConflictError,
+  NotModifiedError,
+} from './common';
+export { ServerResponseError } from './server';
diff --git a/packages/errors/src/error/server.ts b/packages/errors/src/error/server.ts
new file mode 100644
index 0000000000000..a7b89c3baa028
--- /dev/null
+++ b/packages/errors/src/error/server.ts
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  parseServerResponseErrorBody,
+  ServerResponseErrorBody,
+} from '../payload';
+
+/**
+ * An error thrown as the result of a failed server request.
+ *
+ * The server is expected to respond on the ServerResponseErrorBody format.
+ */
+export class ServerResponseError extends Error {
+  static async forResponse(response: Response): Promise<ServerResponseError> {
+    const body = await parseServerResponseErrorBody(response);
+    const status = body.error.statusCode || response.status;
+    const statusText = body.error.name || response.statusText;
+    const message = `Request failed with ${status} ${statusText}`;
+    return new ServerResponseError(message, body);
+  }
+
+  readonly body: ServerResponseErrorBody;
+
+  constructor(message: string, body: ServerResponseErrorBody) {
+    super(message);
+    this.name = 'ServerResponseError';
+    this.body = body;
+  }
+}
diff --git a/packages/errors/src/index.ts b/packages/errors/src/index.ts
new file mode 100644
index 0000000000000..7a85cb2a811bc
--- /dev/null
+++ b/packages/errors/src/index.ts
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export * from './error';
+export * from './payload';
diff --git a/packages/errors/src/payload/ServerResponseErrorBody.test.ts b/packages/errors/src/payload/ServerResponseErrorBody.test.ts
new file mode 100644
index 0000000000000..533b95926ca80
--- /dev/null
+++ b/packages/errors/src/payload/ServerResponseErrorBody.test.ts
@@ -0,0 +1,135 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  parseServerResponseErrorBody,
+  ServerResponseErrorBody,
+} from './ServerResponseErrorBody';
+
+describe('parseServerResponseErrorBody', () => {
+  it('handles the happy path', async () => {
+    const body: ServerResponseErrorBody = {
+      error: {
+        statusCode: 444,
+        name: 'Fours',
+        message: 'Expected fives',
+        stack: 'lines',
+      },
+      request: {
+        method: 'GET',
+        url: '/',
+      },
+    };
+
+    const response: Partial<Response> = {
+      status: 444,
+      statusText: 'Fours',
+      text: async () => JSON.stringify(body),
+      headers: new Headers({ 'Content-Type': 'application/json' }),
+    };
+
+    await expect(
+      parseServerResponseErrorBody(response as Response),
+    ).resolves.toEqual(body);
+  });
+
+  it('uses request header and text body when wrong content type, even if parsable', async () => {
+    const body: ServerResponseErrorBody = {
+      error: {
+        statusCode: 333,
+        name: 'Threes',
+        message: 'Expected twos',
+      },
+      request: {
+        method: 'GET',
+        url: '/',
+      },
+    };
+
+    const response: Partial<Response> = {
+      status: 444,
+      statusText: 'Fours',
+      text: async () => JSON.stringify(body),
+      headers: new Headers({ 'Content-Type': 'not-application/not-json' }),
+    };
+
+    await expect(
+      parseServerResponseErrorBody(response as Response),
+    ).resolves.toEqual({
+      error: {
+        statusCode: 444,
+        name: 'Unknown',
+        message: `Request failed with status 444 Fours, ${JSON.stringify(
+          body,
+        )}`,
+      },
+    });
+  });
+
+  it('uses request header and text body when not parsable', async () => {
+    const body: ServerResponseErrorBody = {
+      error: {
+        statusCode: 333,
+        name: 'Threes',
+        message: 'Expected twos',
+      },
+      request: {
+        method: 'GET',
+        url: '/',
+      },
+    };
+
+    const response: Partial<Response> = {
+      status: 444,
+      statusText: 'Fours',
+      text: async () => JSON.stringify(body).substring(1),
+      headers: new Headers({ 'Content-Type': 'application/json' }),
+    };
+
+    await expect(
+      parseServerResponseErrorBody(response as Response),
+    ).resolves.toEqual({
+      error: {
+        statusCode: 444,
+        name: 'Unknown',
+        message: `Request failed with status 444 Fours, ${JSON.stringify(
+          body,
+        ).substring(1)}`,
+      },
+    });
+  });
+
+  it('uses request header when failing to get body', async () => {
+    const response: Partial<Response> = {
+      status: 444,
+      statusText: 'Fours',
+      text: async () => {
+        throw new Error('bail');
+      },
+      headers: new Headers({ 'Content-Type': 'application/json' }),
+    };
+
+    await expect(
+      parseServerResponseErrorBody(response as Response),
+    ).resolves.toEqual({
+      error: {
+        statusCode: 444,
+        name: 'Unknown',
+        message: `Request failed with status 444 Fours`,
+      },
+    });
+  });
+});
diff --git a/packages/errors/src/payload/ServerResponseErrorBody.ts b/packages/errors/src/payload/ServerResponseErrorBody.ts
new file mode 100644
index 0000000000000..e6f1c80749749
--- /dev/null
+++ b/packages/errors/src/payload/ServerResponseErrorBody.ts
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * A standard shape of JSON data returned as the body of backend errors.
+ */
+export type ServerResponseErrorBody = {
+  /** Details of the error that was caught */
+  error: {
+    /** The numeric HTTP status code that was returned */
+    statusCode: number;
+    /** The name of the exception that was thrown */
+    name: string;
+    /** The message of the exception that was thrown */
+    message: string;
+    /** A stringified stack trace, may not be present */
+    stack?: string;
+  };
+
+  /** The incoming request */
+  request?: {
+    /** The HTTP method of the request */
+    method: string;
+    /** The URL of the request (excluding protocol and host/port) */
+    url: string;
+  };
+};
+
+/**
+ * Attempts to extract the ServerResponseErrorBody out of a server response.
+ * This consumes the body of the response.
+ *
+ * The code is forgiving, and constructs a useful synthetic body as best it can
+ * if the response wasn't on the expected form.
+ *
+ * @param response The response of a failed request
+ */
+export async function parseServerResponseErrorBody(
+  response: Response,
+): Promise<ServerResponseErrorBody> {
+  try {
+    const text = await response.text();
+    if (text) {
+      if (
+        response.headers.get('content-type')?.startsWith('application/json')
+      ) {
+        try {
+          const body = JSON.parse(text);
+          if (body.error && body.request) {
+            return body;
+          }
+        } catch {
+          // ignore
+        }
+      }
+
+      return {
+        error: {
+          statusCode: response.status,
+          name: 'Unknown',
+          message: `Request failed with status ${response.status} ${response.statusText}, ${text}`,
+        },
+      };
+    }
+  } catch {
+    // ignore
+  }
+
+  return {
+    error: {
+      statusCode: response.status,
+      name: 'Unknown',
+      message: `Request failed with status ${response.status} ${response.statusText}`,
+    },
+  };
+}
diff --git a/packages/errors/src/payload/index.ts b/packages/errors/src/payload/index.ts
new file mode 100644
index 0000000000000..238a009dc9698
--- /dev/null
+++ b/packages/errors/src/payload/index.ts
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export { parseServerResponseErrorBody } from './ServerResponseErrorBody';
+export type { ServerResponseErrorBody } from './ServerResponseErrorBody';
diff --git a/packages/errors/src/setupTests.ts b/packages/errors/src/setupTests.ts
new file mode 100644
index 0000000000000..ba33cf996b899
--- /dev/null
+++ b/packages/errors/src/setupTests.ts
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export {};
diff --git a/packages/techdocs-common/package.json b/packages/techdocs-common/package.json
index ed90ea50a626e..bf17cc3d9d32b 100644
--- a/packages/techdocs-common/package.json
+++ b/packages/techdocs-common/package.json
@@ -41,6 +41,7 @@
     "@backstage/backend-common": "^0.5.6",
     "@backstage/catalog-model": "^0.7.4",
     "@backstage/config": "^0.1.3",
+    "@backstage/errors": "^0.1.1",
     "@backstage/integration": "^0.5.1",
     "@google-cloud/storage": "^5.6.0",
     "@types/dockerode": "^3.2.1",
diff --git a/packages/techdocs-common/src/helpers.ts b/packages/techdocs-common/src/helpers.ts
index 856624c5687ec..08a5945e69bd5 100644
--- a/packages/techdocs-common/src/helpers.ts
+++ b/packages/techdocs-common/src/helpers.ts
@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-import { Git, InputError, UrlReader } from '@backstage/backend-common';
+import { Git, UrlReader } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { Entity, parseLocationReference } from '@backstage/catalog-model';
 import { Config } from '@backstage/config';
 import fs from 'fs-extra';
diff --git a/packages/techdocs-common/src/stages/prepare/commonGit.ts b/packages/techdocs-common/src/stages/prepare/commonGit.ts
index c38f5ced9de7f..fecb6cdf0d157 100644
--- a/packages/techdocs-common/src/stages/prepare/commonGit.ts
+++ b/packages/techdocs-common/src/stages/prepare/commonGit.ts
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { NotModifiedError } from '@backstage/backend-common';
+import { NotModifiedError } from '@backstage/errors';
 import { Entity } from '@backstage/catalog-model';
 import { Config } from '@backstage/config';
 import parseGitUrl from 'git-url-parse';
diff --git a/packages/techdocs-common/src/stages/prepare/dir.ts b/packages/techdocs-common/src/stages/prepare/dir.ts
index 08832938dfbed..2f62d88a1cd33 100644
--- a/packages/techdocs-common/src/stages/prepare/dir.ts
+++ b/packages/techdocs-common/src/stages/prepare/dir.ts
@@ -13,11 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import {
-  InputError,
-  NotModifiedError,
-  UrlReader,
-} from '@backstage/backend-common';
+
+import { UrlReader } from '@backstage/backend-common';
+import { InputError, NotModifiedError } from '@backstage/errors';
 import { Entity } from '@backstage/catalog-model';
 import { Config } from '@backstage/config';
 import parseGitUrl from 'git-url-parse';
diff --git a/packages/techdocs-common/src/stages/prepare/url.ts b/packages/techdocs-common/src/stages/prepare/url.ts
index 9e4715a4eee43..8e463698fb216 100644
--- a/packages/techdocs-common/src/stages/prepare/url.ts
+++ b/packages/techdocs-common/src/stages/prepare/url.ts
@@ -13,7 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { NotModifiedError, UrlReader } from '@backstage/backend-common';
+
+import { NotModifiedError } from '@backstage/errors';
+import { UrlReader } from '@backstage/backend-common';
 import { Entity } from '@backstage/catalog-model';
 import { Logger } from 'winston';
 import { getDocFilesFromRepository } from '../../helpers';
diff --git a/plugins/auth-backend/package.json b/plugins/auth-backend/package.json
index 5528603529401..f1c334cf75fda 100644
--- a/plugins/auth-backend/package.json
+++ b/plugins/auth-backend/package.json
@@ -33,6 +33,7 @@
     "@backstage/catalog-client": "^0.3.7",
     "@backstage/catalog-model": "^0.7.4",
     "@backstage/config": "^0.1.3",
+    "@backstage/errors": "^0.1.1",
     "@backstage/test-utils": "^0.1.8",
     "@types/express": "^4.17.6",
     "@types/passport": "^1.0.3",
diff --git a/plugins/auth-backend/src/lib/catalog/CatalogIdentityClient.ts b/plugins/auth-backend/src/lib/catalog/CatalogIdentityClient.ts
index e1a35533941e5..abd3624df2107 100644
--- a/plugins/auth-backend/src/lib/catalog/CatalogIdentityClient.ts
+++ b/plugins/auth-backend/src/lib/catalog/CatalogIdentityClient.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { ConflictError, NotFoundError } from '@backstage/backend-common';
+import { ConflictError, NotFoundError } from '@backstage/errors';
 import { CatalogApi } from '@backstage/catalog-client';
 import { UserEntity } from '@backstage/catalog-model';
 
diff --git a/plugins/auth-backend/src/lib/oauth/OAuthAdapter.ts b/plugins/auth-backend/src/lib/oauth/OAuthAdapter.ts
index d6454fd8071bb..6cf6a949647e9 100644
--- a/plugins/auth-backend/src/lib/oauth/OAuthAdapter.ts
+++ b/plugins/auth-backend/src/lib/oauth/OAuthAdapter.ts
@@ -22,7 +22,7 @@ import {
   BackstageIdentity,
   AuthProviderConfig,
 } from '../../providers/types';
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { TokenIssuer } from '../../identity';
 import { verifyNonce } from './helpers';
 import { postMessageResponse, ensuresXRequestedWith } from '../flow';
diff --git a/plugins/auth-backend/src/lib/oauth/OAuthEnvironmentHandler.ts b/plugins/auth-backend/src/lib/oauth/OAuthEnvironmentHandler.ts
index d22fc5249920d..9998a5b10ce23 100644
--- a/plugins/auth-backend/src/lib/oauth/OAuthEnvironmentHandler.ts
+++ b/plugins/auth-backend/src/lib/oauth/OAuthEnvironmentHandler.ts
@@ -16,7 +16,7 @@
 
 import express from 'express';
 import { Config } from '@backstage/config';
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { readState } from './helpers';
 import { AuthProviderRouteHandlers } from '../../providers/types';
 
diff --git a/plugins/auth-backend/src/service/router.ts b/plugins/auth-backend/src/service/router.ts
index 85d60661e9f8c..afc58ecbf3b1c 100644
--- a/plugins/auth-backend/src/service/router.ts
+++ b/plugins/auth-backend/src/service/router.ts
@@ -23,10 +23,10 @@ import {
   AuthProviderFactory,
 } from '../providers';
 import {
-  NotFoundError,
   PluginDatabaseManager,
   PluginEndpointDiscovery,
 } from '@backstage/backend-common';
+import { NotFoundError } from '@backstage/errors';
 import { CatalogClient } from '@backstage/catalog-client';
 import { Config } from '@backstage/config';
 import { createOidcRouter, DatabaseKeyStore, TokenFactory } from '../identity';
diff --git a/plugins/catalog-backend/package.json b/plugins/catalog-backend/package.json
index 0d0aa5057ea10..204c6f4002d26 100644
--- a/plugins/catalog-backend/package.json
+++ b/plugins/catalog-backend/package.json
@@ -33,6 +33,7 @@
     "@backstage/backend-common": "^0.5.6",
     "@backstage/catalog-model": "^0.7.4",
     "@backstage/config": "^0.1.3",
+    "@backstage/errors": "^0.1.1",
     "@backstage/integration": "^0.5.1",
     "@octokit/graphql": "^4.5.8",
     "@types/express": "^4.17.6",
diff --git a/plugins/catalog-backend/src/catalog/DatabaseEntitiesCatalog.ts b/plugins/catalog-backend/src/catalog/DatabaseEntitiesCatalog.ts
index b03183cf344bb..7cc88b9f183f1 100644
--- a/plugins/catalog-backend/src/catalog/DatabaseEntitiesCatalog.ts
+++ b/plugins/catalog-backend/src/catalog/DatabaseEntitiesCatalog.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { ConflictError, NotFoundError } from '@backstage/backend-common';
+import { ConflictError, NotFoundError } from '@backstage/errors';
 import {
   Entity,
   entityHasChanges,
diff --git a/plugins/catalog-backend/src/database/CommonDatabase.test.ts b/plugins/catalog-backend/src/database/CommonDatabase.test.ts
index b319bb832df37..0e26384358f6f 100644
--- a/plugins/catalog-backend/src/database/CommonDatabase.test.ts
+++ b/plugins/catalog-backend/src/database/CommonDatabase.test.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { ConflictError } from '@backstage/backend-common';
+import { ConflictError } from '@backstage/errors';
 import { Entity, Location, parseEntityRef } from '@backstage/catalog-model';
 import { EntityFilters } from '../service/EntityFilters';
 import { DatabaseManager } from './DatabaseManager';
diff --git a/plugins/catalog-backend/src/database/CommonDatabase.ts b/plugins/catalog-backend/src/database/CommonDatabase.ts
index cc83350019b6c..890ce48e0c3fc 100644
--- a/plugins/catalog-backend/src/database/CommonDatabase.ts
+++ b/plugins/catalog-backend/src/database/CommonDatabase.ts
@@ -14,11 +14,7 @@
  * limitations under the License.
  */
 
-import {
-  ConflictError,
-  InputError,
-  NotFoundError,
-} from '@backstage/backend-common';
+import { ConflictError, InputError, NotFoundError } from '@backstage/errors';
 import {
   Entity,
   EntityName,
diff --git a/plugins/catalog-backend/src/ingestion/LocationReaders.ts b/plugins/catalog-backend/src/ingestion/LocationReaders.ts
index be88aa28100db..a7b00c2a4fe83 100644
--- a/plugins/catalog-backend/src/ingestion/LocationReaders.ts
+++ b/plugins/catalog-backend/src/ingestion/LocationReaders.ts
@@ -14,13 +14,15 @@
  * limitations under the License.
  */
 
-import { NotAllowedError, UrlReader } from '@backstage/backend-common';
+import { NotAllowedError } from '@backstage/errors';
+import { UrlReader } from '@backstage/backend-common';
 import {
   Entity,
   EntityPolicy,
   EntityRelationSpec,
   ENTITY_DEFAULT_NAMESPACE,
   LocationSpec,
+  stringifyLocationReference,
 } from '@backstage/catalog-model';
 import { Config } from '@backstage/config';
 import { Logger } from 'winston';
@@ -103,7 +105,11 @@ export class LocationReaders implements LocationReader {
             output.errors.push({
               location: item.location,
               error: new NotAllowedError(
-                `Entity of kind ${item.entity.kind} is not allowed from location ${item.location.type} ${item.location.target}`,
+                `Entity of kind ${
+                  item.entity.kind
+                } is not allowed from location ${stringifyLocationReference(
+                  item.location,
+                )}`,
               ),
             });
           }
@@ -166,14 +172,20 @@ export class LocationReaders implements LocationReader {
             return;
           }
         } catch (e) {
-          const message = `Processor ${processor.constructor.name} threw an error while reading location ${item.location.type} ${item.location.target}, ${e}`;
+          const message = `Processor ${
+            processor.constructor.name
+          } threw an error while reading location ${stringifyLocationReference(
+            item.location,
+          )}, ${e}`;
           emit(result.generalError(item.location, message));
           logger.warn(message);
         }
       }
     }
 
-    const message = `No processor was able to read location ${item.location.type} ${item.location.target}`;
+    const message = `No processor was able to read location ${stringifyLocationReference(
+      item.location,
+    )}`;
     emit(result.inputError(item.location, message));
     logger.warn(message);
   }
@@ -205,7 +217,11 @@ export class LocationReaders implements LocationReader {
             originLocation,
           );
         } catch (e) {
-          const message = `Processor ${processor.constructor.name} threw an error while preprocessing entity ${kind}:${namespace}/${name} at ${item.location.type} ${item.location.target}, ${e}`;
+          const message = `Processor ${
+            processor.constructor.name
+          } threw an error while preprocessing entity ${kind}:${namespace}/${name} at ${stringifyLocationReference(
+            item.location,
+          )}, ${e}`;
           emit(result.generalError(item.location, e.message));
           logger.warn(message);
           return undefined;
@@ -216,14 +232,18 @@ export class LocationReaders implements LocationReader {
     try {
       const next = await this.options.policy.enforce(current);
       if (!next) {
-        const message = `Policy unexpectedly returned no data while analyzing entity ${kind}:${namespace}/${name} at ${item.location.type} ${item.location.target}`;
+        const message = `Policy unexpectedly returned no data while analyzing entity ${kind}:${namespace}/${name} at ${stringifyLocationReference(
+          item.location,
+        )}`;
         emit(result.generalError(item.location, message));
         logger.warn(message);
         return undefined;
       }
       current = next;
     } catch (e) {
-      const message = `Policy check failed while analyzing entity ${kind}:${namespace}/${name} at ${item.location.type} ${item.location.target}, ${e}`;
+      const message = `Policy check failed while analyzing entity ${kind}:${namespace}/${name} at ${stringifyLocationReference(
+        item.location,
+      )}, ${e}`;
       emit(result.inputError(item.location, e.message));
       logger.warn(message);
       return undefined;
@@ -238,7 +258,11 @@ export class LocationReaders implements LocationReader {
             break;
           }
         } catch (e) {
-          const message = `Processor ${processor.constructor.name} threw an error while validating the entity ${kind}:${namespace}/${name} at ${item.location.type} ${item.location.target}, ${e}`;
+          const message = `Processor ${
+            processor.constructor.name
+          } threw an error while validating the entity ${kind}:${namespace}/${name} at ${stringifyLocationReference(
+            item.location,
+          )}, ${e}`;
           emit(result.inputError(item.location, message));
           logger.warn(message);
           return undefined;
@@ -246,7 +270,9 @@ export class LocationReaders implements LocationReader {
       }
     }
     if (!handled) {
-      const message = `No processor recognized the entity ${kind}:${namespace}/${name} at ${item.location.type} ${item.location.target}`;
+      const message = `No processor recognized the entity ${kind}:${namespace}/${name} at ${stringifyLocationReference(
+        item.location,
+      )}`;
       emit(result.inputError(item.location, message));
       logger.warn(message);
       return undefined;
@@ -261,7 +287,11 @@ export class LocationReaders implements LocationReader {
             emit,
           );
         } catch (e) {
-          const message = `Processor ${processor.constructor.name} threw an error while postprocessing entity ${kind}:${namespace}/${name} at ${item.location.type} ${item.location.target}, ${e}`;
+          const message = `Processor ${
+            processor.constructor.name
+          } threw an error while postprocessing entity ${kind}:${namespace}/${name} at ${stringifyLocationReference(
+            item.location,
+          )}, ${e}`;
           emit(result.generalError(item.location, message));
           logger.warn(message);
           return undefined;
@@ -279,7 +309,9 @@ export class LocationReaders implements LocationReader {
     const { processors, logger } = this.options;
 
     logger.debug(
-      `Encountered error at location ${item.location.type} ${item.location.target}, ${item.error}`,
+      `Encountered error at location ${stringifyLocationReference(
+        item.location,
+      )}, ${item.error}`,
     );
 
     const validatedEmit: CatalogProcessorEmit = emitResult => {
@@ -295,7 +327,11 @@ export class LocationReaders implements LocationReader {
         try {
           await processor.handleError(item.error, item.location, validatedEmit);
         } catch (e) {
-          const message = `Processor ${processor.constructor.name} threw an error while handling another error at ${item.location.type} ${item.location.target}, ${e}`;
+          const message = `Processor ${
+            processor.constructor.name
+          } threw an error while handling another error at ${stringifyLocationReference(
+            item.location,
+          )}, ${e}`;
           emit(result.generalError(item.location, message));
           logger.warn(message);
         }
diff --git a/plugins/catalog-backend/src/ingestion/processors/CodeOwnersProcessor.ts b/plugins/catalog-backend/src/ingestion/processors/CodeOwnersProcessor.ts
index bdea197426366..3855335eb93bb 100644
--- a/plugins/catalog-backend/src/ingestion/processors/CodeOwnersProcessor.ts
+++ b/plugins/catalog-backend/src/ingestion/processors/CodeOwnersProcessor.ts
@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-import { NotFoundError, UrlReader } from '@backstage/backend-common';
+import { UrlReader } from '@backstage/backend-common';
+import { NotFoundError } from '@backstage/errors';
 import {
   Entity,
   LocationSpec,
diff --git a/plugins/catalog-backend/src/ingestion/processors/results.ts b/plugins/catalog-backend/src/ingestion/processors/results.ts
index 5f92087cec20f..da2089adc11ae 100644
--- a/plugins/catalog-backend/src/ingestion/processors/results.ts
+++ b/plugins/catalog-backend/src/ingestion/processors/results.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError, NotFoundError } from '@backstage/backend-common';
+import { InputError, NotFoundError } from '@backstage/errors';
 import {
   Entity,
   EntityRelationSpec,
diff --git a/plugins/catalog-backend/src/service/EntityFilters.ts b/plugins/catalog-backend/src/service/EntityFilters.ts
index 5a93407424a67..83c0bfea6c24f 100644
--- a/plugins/catalog-backend/src/service/EntityFilters.ts
+++ b/plugins/catalog-backend/src/service/EntityFilters.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { EntitiesSearchFilter, EntityFilter } from '../database';
 
 /**
diff --git a/plugins/catalog-backend/src/service/filterQuery.ts b/plugins/catalog-backend/src/service/filterQuery.ts
index e9b6ef6062602..5e6b18ddf1d61 100644
--- a/plugins/catalog-backend/src/service/filterQuery.ts
+++ b/plugins/catalog-backend/src/service/filterQuery.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { Entity } from '@backstage/catalog-model';
 import lodash from 'lodash';
 import { RecursivePartial } from '../util';
diff --git a/plugins/catalog-backend/src/service/router.test.ts b/plugins/catalog-backend/src/service/router.test.ts
index cef40a9aac834..f7655b859e32f 100644
--- a/plugins/catalog-backend/src/service/router.test.ts
+++ b/plugins/catalog-backend/src/service/router.test.ts
@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-import { getVoidLogger, NotFoundError } from '@backstage/backend-common';
+import { getVoidLogger } from '@backstage/backend-common';
+import { NotFoundError } from '@backstage/errors';
 import type { Entity, LocationSpec } from '@backstage/catalog-model';
 import express from 'express';
 import request from 'supertest';
diff --git a/plugins/catalog-backend/src/service/router.ts b/plugins/catalog-backend/src/service/router.ts
index 5936e3a747aa7..78ef2e09ac459 100644
--- a/plugins/catalog-backend/src/service/router.ts
+++ b/plugins/catalog-backend/src/service/router.ts
@@ -14,20 +14,21 @@
  * limitations under the License.
  */
 
-import { errorHandler, NotFoundError } from '@backstage/backend-common';
+import { errorHandler } from '@backstage/backend-common';
+import { NotFoundError } from '@backstage/errors';
+import type { Entity } from '@backstage/catalog-model';
 import {
-  locationSpecSchema,
   analyzeLocationSchema,
+  locationSpecSchema,
 } from '@backstage/catalog-model';
-import type { Entity } from '@backstage/catalog-model';
 import express from 'express';
 import Router from 'express-promise-router';
 import { Logger } from 'winston';
 import yn from 'yn';
 import { EntitiesCatalog, LocationsCatalog } from '../catalog';
-import { LocationAnalyzer, HigherOrderOperation } from '../ingestion/types';
-import { translateQueryToFieldMapper } from './filterQuery';
+import { HigherOrderOperation, LocationAnalyzer } from '../ingestion/types';
 import { EntityFilters } from './EntityFilters';
+import { translateQueryToFieldMapper } from './filterQuery';
 import { requireRequestBody, validateRequestBody } from './util';
 
 export interface RouterOptions {
@@ -105,7 +106,7 @@ export async function createRouter(
         );
         if (!entities.length) {
           throw new NotFoundError(
-            `No entity with kind ${kind} namespace ${namespace} name ${name}`,
+            `No entity named '${name}' found, with kind '${kind}' in namespace '${namespace}'`,
           );
         }
         res.status(200).json(entities[0]);
diff --git a/plugins/catalog-backend/src/service/util.ts b/plugins/catalog-backend/src/service/util.ts
index 39692030e36fd..d806f630e8a03 100644
--- a/plugins/catalog-backend/src/service/util.ts
+++ b/plugins/catalog-backend/src/service/util.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { Request } from 'express';
 import lodash from 'lodash';
 import yup from 'yup';
diff --git a/plugins/catalog/src/components/EntityPageLayout/EntityPageLayout.tsx b/plugins/catalog/src/components/EntityPageLayout/EntityPageLayout.tsx
index 6f9899ff82588..7109f4beb378b 100644
--- a/plugins/catalog/src/components/EntityPageLayout/EntityPageLayout.tsx
+++ b/plugins/catalog/src/components/EntityPageLayout/EntityPageLayout.tsx
@@ -20,6 +20,7 @@ import {
 } from '@backstage/catalog-model';
 import {
   Content,
+  ErrorResponsePanel,
   Header,
   HeaderLabel,
   Link,
@@ -34,7 +35,6 @@ import {
   useEntityCompoundName,
 } from '@backstage/plugin-catalog-react';
 import { Box } from '@material-ui/core';
-import { Alert } from '@material-ui/lab';
 import React, { PropsWithChildren, useContext, useState } from 'react';
 import { useNavigate } from 'react-router';
 import { EntityContextMenu } from '../EntityContextMenu/EntityContextMenu';
@@ -143,7 +143,7 @@ export const EntityPageLayout = ({ children }: PropsWithChildren<{}>) => {
 
       {error && (
         <Content>
-          <Alert severity="error">{error.toString()}</Alert>
+          <ErrorResponsePanel error={error} />
         </Content>
       )}
 
diff --git a/plugins/scaffolder-backend/package.json b/plugins/scaffolder-backend/package.json
index f4aa5cf1ce621..9a23c588db768 100644
--- a/plugins/scaffolder-backend/package.json
+++ b/plugins/scaffolder-backend/package.json
@@ -33,6 +33,7 @@
     "@backstage/catalog-client": "^0.3.7",
     "@backstage/catalog-model": "^0.7.4",
     "@backstage/config": "^0.1.3",
+    "@backstage/errors": "^0.1.1",
     "@backstage/integration": "^0.5.1",
     "@gitbeaker/core": "^28.0.2",
     "@gitbeaker/node": "^28.0.2",
diff --git a/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
index 46a1433be2c31..806f3ecad5af4 100644
--- a/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
+++ b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
@@ -19,7 +19,7 @@ import {
   TemplateEntityV1beta2,
 } from '@backstage/catalog-model';
 import { CatalogApi } from '@backstage/catalog-client';
-import { ConflictError, NotFoundError } from '@backstage/backend-common';
+import { ConflictError, NotFoundError } from '@backstage/errors';
 
 /**
  * A catalog client tailored for reading out entity data from the catalog.
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/TemplateActionRegistry.ts b/plugins/scaffolder-backend/src/scaffolder/actions/TemplateActionRegistry.ts
index c9e163bfdd889..4f8042336c73b 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/TemplateActionRegistry.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/TemplateActionRegistry.ts
@@ -15,7 +15,7 @@
  */
 
 import { InputBase, TemplateAction } from './types';
-import { ConflictError, NotFoundError } from '@backstage/backend-common';
+import { ConflictError, NotFoundError } from '@backstage/errors';
 
 export class TemplateActionRegistry {
   private readonly actions = new Map<string, TemplateAction<any>>();
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/catalog/register.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/catalog/register.ts
index b034b480e2fd3..8ee98f5d20c99 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/catalog/register.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/catalog/register.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { ScmIntegrations } from '@backstage/integration';
 import { CatalogApi } from '@backstage/catalog-client';
 import { getEntityName } from '@backstage/catalog-model';
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/cookiecutter.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/cookiecutter.ts
index 070aaa9679e11..814146cc5030c 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/cookiecutter.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/cookiecutter.ts
@@ -17,7 +17,8 @@
 import fs from 'fs-extra';
 import { resolve as resolvePath } from 'path';
 import Docker from 'dockerode';
-import { InputError, UrlReader } from '@backstage/backend-common';
+import { UrlReader } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { ScmIntegrations } from '@backstage/integration';
 import { JsonObject } from '@backstage/config';
 import { TemplaterBuilder, TemplaterValues } from '../../../stages/templater';
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/helpers.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/helpers.ts
index 652a1a56cae36..67fe9533aabe8 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/helpers.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/helpers.ts
@@ -16,7 +16,8 @@
 
 import fs from 'fs-extra';
 import { resolve as resolvePath, isAbsolute } from 'path';
-import { InputError, UrlReader } from '@backstage/backend-common';
+import { UrlReader } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { ScmIntegrations } from '@backstage/integration';
 import { JsonValue } from '@backstage/config';
 
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/plain.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/plain.ts
index 00c63535ca55f..08316e95e6938 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/plain.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/plain.ts
@@ -15,7 +15,8 @@
  */
 
 import path from 'path';
-import { InputError, UrlReader } from '@backstage/backend-common';
+import { UrlReader } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { ScmIntegrations } from '@backstage/integration';
 import { fetchContents } from './helpers';
 import { createTemplateAction } from '../../createTemplateAction';
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/azure.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/azure.ts
index db3896008661c..0141de349921b 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/azure.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/azure.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { ScmIntegrationRegistry } from '@backstage/integration';
 import { initRepoAndPush } from '../../../stages/publish/helpers';
 import { GitRepositoryCreateOptions } from 'azure-devops-node-api/interfaces/GitInterfaces';
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/bitbucket.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/bitbucket.ts
index 03881af35ddbf..a7370356cc846 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/bitbucket.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/bitbucket.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import {
   BitbucketIntegrationConfig,
   ScmIntegrationRegistry,
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/github.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/github.ts
index cb11e3d08ae50..4f9b6038a152e 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/github.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/github.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import {
   GithubCredentialsProvider,
   ScmIntegrationRegistry,
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/gitlab.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/gitlab.ts
index eefdcdf11b0ab..12fc90cc94875 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/gitlab.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/gitlab.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { ScmIntegrationRegistry } from '@backstage/integration';
 import { Gitlab } from '@gitbeaker/node';
 import { initRepoAndPush } from '../../../stages/publish/helpers';
diff --git a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/util.ts b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/util.ts
index 9349d5b5eb8b2..89bbf24574430 100644
--- a/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/util.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/actions/builtin/publish/util.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 
 export const parseRepoUrl = (repoUrl: string) => {
   let parsed;
diff --git a/plugins/scaffolder-backend/src/scaffolder/stages/helpers.ts b/plugins/scaffolder-backend/src/scaffolder/stages/helpers.ts
index 924b9f5811072..b4e13e3ad4078 100644
--- a/plugins/scaffolder-backend/src/scaffolder/stages/helpers.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/stages/helpers.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import {
   LOCATION_ANNOTATION,
   parseLocationReference,
diff --git a/plugins/scaffolder-backend/src/scaffolder/stages/prepare/file.ts b/plugins/scaffolder-backend/src/scaffolder/stages/prepare/file.ts
index 687cc394520c4..9eb380be13e90 100644
--- a/plugins/scaffolder-backend/src/scaffolder/stages/prepare/file.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/stages/prepare/file.ts
@@ -16,7 +16,7 @@
 import fs from 'fs-extra';
 import path from 'path';
 import { fileURLToPath } from 'url';
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { PreparerBase, PreparerOptions } from './types';
 
 export class FilePreparer implements PreparerBase {
diff --git a/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts b/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts
index cb1e8532f26d6..f5080907df4c3 100644
--- a/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 import { spawn } from 'child_process';
 import { PassThrough, Writable } from 'stream';
diff --git a/plugins/scaffolder-backend/src/scaffolder/tasks/DatabaseTaskStore.ts b/plugins/scaffolder-backend/src/scaffolder/tasks/DatabaseTaskStore.ts
index f3d7766d862bc..91264bd3e2cd9 100644
--- a/plugins/scaffolder-backend/src/scaffolder/tasks/DatabaseTaskStore.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/tasks/DatabaseTaskStore.ts
@@ -15,11 +15,8 @@
  */
 
 import { JsonObject } from '@backstage/config';
-import {
-  ConflictError,
-  NotFoundError,
-  resolvePackagePath,
-} from '@backstage/backend-common';
+import { resolvePackagePath } from '@backstage/backend-common';
+import { ConflictError, NotFoundError } from '@backstage/errors';
 import { Knex } from 'knex';
 import { v4 as uuid } from 'uuid';
 import {
diff --git a/plugins/scaffolder-backend/src/scaffolder/tasks/TaskWorker.ts b/plugins/scaffolder-backend/src/scaffolder/tasks/TaskWorker.ts
index bd0a418598ea0..3a846f79a5f13 100644
--- a/plugins/scaffolder-backend/src/scaffolder/tasks/TaskWorker.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/tasks/TaskWorker.ts
@@ -24,7 +24,7 @@ import fs from 'fs-extra';
 import path from 'path';
 import { TemplateActionRegistry } from '../actions/TemplateActionRegistry';
 import * as handlebars from 'handlebars';
-import { InputError } from '@backstage/backend-common';
+import { InputError } from '@backstage/errors';
 
 type Options = {
   logger: Logger;
diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index 81be03730b4f8..ec7e79bbc81cc 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -42,12 +42,8 @@ import { templateEntityToSpec } from '../scaffolder/tasks/TemplateConverter';
 import { TemplateActionRegistry } from '../scaffolder/actions/TemplateActionRegistry';
 import { createLegacyActions } from '../scaffolder/stages/legacy';
 import { getEntityBaseUrl, getWorkingDirectory } from './helpers';
-import {
-  InputError,
-  NotFoundError,
-  PluginDatabaseManager,
-  UrlReader,
-} from '@backstage/backend-common';
+import { PluginDatabaseManager, UrlReader } from '@backstage/backend-common';
+import { InputError, NotFoundError } from '@backstage/errors';
 import { CatalogApi } from '@backstage/catalog-client';
 import {
   TemplateEntityV1alpha1,
diff --git a/plugins/techdocs-backend/package.json b/plugins/techdocs-backend/package.json
index f3a87ff569183..4e716dab32721 100644
--- a/plugins/techdocs-backend/package.json
+++ b/plugins/techdocs-backend/package.json
@@ -33,6 +33,7 @@
     "@backstage/backend-common": "^0.5.6",
     "@backstage/catalog-model": "^0.7.4",
     "@backstage/config": "^0.1.3",
+    "@backstage/errors": "^0.1.1",
     "@backstage/techdocs-common": "^0.4.4",
     "@types/dockerode": "^3.2.1",
     "@types/express": "^4.17.6",
diff --git a/plugins/techdocs-backend/src/DocsBuilder/builder.ts b/plugins/techdocs-backend/src/DocsBuilder/builder.ts
index 50577ab130165..f42a708bb29f1 100644
--- a/plugins/techdocs-backend/src/DocsBuilder/builder.ts
+++ b/plugins/techdocs-backend/src/DocsBuilder/builder.ts
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { NotModifiedError } from '@backstage/backend-common';
+import { NotModifiedError } from '@backstage/errors';
 import { Entity, serializeEntityRef } from '@backstage/catalog-model';
 import {
   GeneratorBase,