diff --git a/.publishrc b/.publishrc
index 7d39c002..5bb40572 100644
--- a/.publishrc
+++ b/.publishrc
@@ -14,6 +14,6 @@
   "confirm": true,
   "publishCommand": "npm publish",
   "publishTag": "latest",
-  "prePublishScript": "npm test",
+  "prePublishScript": "npm test && npm test-types",
   "postPublishScript": false
 }
\ No newline at end of file
diff --git a/package.json b/package.json
index 2ed0e05b..df0f3102 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
   "main": "./src/fxp.js",
   "scripts": {
     "test": "nyc --reporter=lcov --reporter=text jasmine spec/*spec.js",
+    "test-types": "tsc --noEmit spec/typings/typings-test.ts",
     "unit": "jasmine",
     "coverage": "nyc report --reporter html --reporter text -t .nyc_output --report-dir .nyc_output/summary",
     "perf": "node ./benchmark/perfTest3.js",
@@ -46,6 +47,7 @@
     "@babel/plugin-transform-runtime": "^7.13.10",
     "@babel/preset-env": "^7.13.10",
     "@babel/register": "^7.13.8",
+    "@types/node": "20",
     "babel-loader": "^8.2.2",
     "cytorus": "^0.2.9",
     "eslint": "^8.3.0",
@@ -54,6 +56,7 @@
     "nyc": "^15.1.0",
     "prettier": "^1.19.1",
     "publish-please": "^5.5.2",
+    "typescript": "5",
     "webpack": "^5.64.4",
     "webpack-cli": "^4.9.1"
   },
diff --git a/spec/typings/typings-test.ts b/spec/typings/typings-test.ts
new file mode 100644
index 00000000..3d35951f
--- /dev/null
+++ b/spec/typings/typings-test.ts
@@ -0,0 +1,47 @@
+import {
+    XMLParser,
+    XMLBuilder,
+    XMLValidator,
+    type X2jOptions,
+    type XmlBuilderOptions,
+    type validationOptions,
+} from '../../src/fxp';
+
+const parseOpts: X2jOptions = {};
+
+const XML = `
+    <?xml version="1.0"?>
+    <SomeElement name="parent">
+        <SomeNestedElement name="child"></SomeNestedElement>
+    </SomeElement>
+`;
+
+const parser = new XMLParser(parseOpts);
+const parsed = parser.parse(XML);
+
+console.log(!!parsed);
+
+const buildOpts: XmlBuilderOptions = {};
+
+const builder = new XMLBuilder(buildOpts);
+
+const built = builder.build({
+    any_name: {
+        person: {
+            phone: [
+                15555551313,
+                15555551212
+            ]
+        }
+    }
+});
+
+console.log(!!built);
+
+const validateOpts: validationOptions = {};
+
+const isValid = XMLValidator.validate(built, validateOpts);
+
+console.log(!!isValid);
+
+
diff --git a/src/fxp.d.ts b/src/fxp.d.ts
index d622f27e..ada4502a 100644
--- a/src/fxp.d.ts
+++ b/src/fxp.d.ts
@@ -1,81 +1,375 @@
 type X2jOptions = {
-  preserveOrder: boolean;
-  attributeNamePrefix: string;
-  attributesGroupName: false | string;
-  textNodeName: string;
-  ignoreAttributes: boolean;
-  removeNSPrefix: boolean;
-  allowBooleanAttributes: boolean;
-  parseTagValue: boolean;
-  parseAttributeValue: boolean;
-  trimValues: boolean;
-  cdataPropName: false | string;
-  commentPropName: false | string;
-    /**
-Control how tag value should be parsed. Called only if tag value is not empty
-
-@returns {undefined|null} `undefined` or `null` to set original value.
-@returns {unknown} 
-1. Different value or value with different data type to set new value. <br>
-2. Same value to set parsed value if `parseTagValue: true`.
-   */
-  tagValueProcessor: (tagName: string, tagValue: string, jPath: string, hasAttributes: boolean, isLeafNode: boolean) => unknown;
-  attributeValueProcessor: (attrName: string, attrValue: string, jPath: string) => unknown;
-  numberParseOptions: strnumOptions;
-  stopNodes: string[];
-  unpairedTags: string[];
-  alwaysCreateTextNode: boolean;
-  isArray: (tagName: string, jPath: string, isLeafNode: boolean, isAttribute: boolean) => boolean;
-  processEntities: boolean;
-  htmlEntities: boolean;
-  ignoreDeclaration: boolean;
-  ignorePiTags: boolean;
-  transformTagName: ((tagName: string) => string) | false;
-  transformAttributeName: ((attributeName: string) => string) | false;
-    /**
-Change the tag name when a different name is returned. Skip the tag from parsed result when false is returned. 
-Modify `attrs` object to control attributes for the given tag.
-
-@returns {string} new tag name.
-@returns false to skip the tag
-   */
-  updateTag: (tagName: string, jPath: string, attrs: {[k: string]: string}) =>  string | boolean;
+  /**
+   * Preserve the order of tags in resulting JS object
+   * 
+   * Defaults to `false`
+   */
+  preserveOrder?: boolean;
+
+  /**
+   * Give a prefix to the attribute name in the resulting JS object
+   * 
+   * Defaults to '@_'
+   */  
+  attributeNamePrefix?: string;
+
+  /**
+   * A name to group all attributes of a tag under, or `false` to disable
+   * 
+   * Defaults to `false`
+   */
+  attributesGroupName?: false | string;
+
+  /**
+   * The name of the next node in the resulting JS
+   * 
+   * Defaults to `#text`
+   */
+  textNodeName?: string;
+
+  /**
+   * Whether to ignore attributes when parsing
+   * 
+   * Defaults to `true`
+   */
+  ignoreAttributes?: boolean;
+
+  /**
+   * Whether to remove namespace string from tag and attribute names
+   * 
+   * Defaults to `false`
+   */
+  removeNSPrefix?: boolean;
+
+  /**
+   * Whether to allow attributes without value
+   * 
+   * Defaults to `false`
+   */
+  allowBooleanAttributes?: boolean;
+
+  /**
+   * Whether to parse tag value with `strnum` package
+   * 
+   * Defaults to `true`
+   */
+  parseTagValue?: boolean;
+
+  /**
+   * Whether to parse tag value with `strnum` package
+   * 
+   * Defaults to `false`
+   */
+  parseAttributeValue?: boolean;
+
+  /**
+   * Whether to remove surrounding whitespace from tag or attribute value
+   * 
+   * Defaults to `true`
+   */
+  trimValues?: boolean;
+
+  /**
+   * Give a property name to set CDATA values to instead of merging to tag's text value
+   * 
+   * Defaults to `false`
+   */
+  cdataPropName?: false | string;
+
+  /**
+   * If set, parse comments and set as this property
+   * 
+   * Defaults to `false`
+   */
+  commentPropName?: false | string;
+
+  /**
+   * Control how tag value should be parsed. Called only if tag value is not empty
+   * 
+   * @returns {undefined|null} `undefined` or `null` to set original value.
+   * @returns {unknown} 
+   * 
+   * 1. Different value or value with different data type to set new value.
+   * 2. Same value to set parsed value if `parseTagValue: true`.
+   * 
+   * Defaults to `(tagName, val, jPath, hasAttributes, isLeafNode) => val`
+   */
+  tagValueProcessor?: (tagName: string, tagValue: string, jPath: string, hasAttributes: boolean, isLeafNode: boolean) => unknown;
+
+  /**
+   * Control how attribute value should be parsed
+   * 
+   * @param attrName 
+   * @param attrValue 
+   * @param jPath 
+   * @returns {undefined|null} `undefined` or `null` to set original value
+   * @returns {unknown}
+   * 
+   * Defaults to `(attrName, val, jPath) => val`
+   */
+  attributeValueProcessor?: (attrName: string, attrValue: string, jPath: string) => unknown;
+
+  /**
+   * Options to pass to `strnum` for parsing numbers
+   * 
+   * Defaults to `{ hex: true, leadingZeros: true, eNotation: true }`
+   */
+  numberParseOptions?: strnumOptions;
+
+  /**
+   * Nodes to stop parsing at
+   * 
+   * Defaults to `[]`
+   */
+  stopNodes?: string[];
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+
+  /**
+   * Whether to always create a text node
+   * 
+   * Defaults to `false`
+   */
+  alwaysCreateTextNode?: boolean;
+
+  /**
+   * Determine whether a tag should be parsed as an array
+   * 
+   * @param tagName 
+   * @param jPath 
+   * @param isLeafNode 
+   * @param isAttribute 
+   * @returns {boolean}
+   * 
+   * Defaults to `() => false`
+   */
+  isArray?: (tagName: string, jPath: string, isLeafNode: boolean, isAttribute: boolean) => boolean;
+
+  /**
+   * Whether to process default and DOCTYPE entities
+   * 
+   * Defaults to `true`
+   */
+  processEntities?: boolean;
+
+  /**
+   * Whether to process HTML entities
+   * 
+   * Defaults to `false`
+   */
+  htmlEntities?: boolean;
+
+  /**
+   * Whether to ignore the declaration tag from output
+   * 
+   * Defaults to `false`
+   */
+  ignoreDeclaration?: boolean;
+
+  /**
+   * Whether to ignore Pi tags
+   * 
+   * Defaults to `false`
+   */
+  ignorePiTags?: boolean;
+
+  /**
+   * Transform tag names
+   * 
+   * Defaults to `false`
+   */
+  transformTagName?: ((tagName: string) => string) | false;
+
+  /**
+   * Transform attribute names
+   * 
+   * Defaults to `false`
+   */
+  transformAttributeName?: ((attributeName: string) => string) | false;
+
+  /**
+   * Change the tag name when a different name is returned. Skip the tag from parsed result when false is returned.
+   * Modify `attrs` object to control attributes for the given tag.
+   * 
+   * @returns {string} new tag name.
+   * @returns false to skip the tag
+   * 
+   * Defaults to `(tagName, jPath, attrs) => tagName`
+   */
+  updateTag?: (tagName: string, jPath: string, attrs: {[k: string]: string}) =>  string | boolean;
 };
+
 type strnumOptions = {
   hex: boolean;
   leadingZeros: boolean,
   skipLike?: RegExp,
   eNotation?: boolean
 }
-type X2jOptionsOptional = Partial<X2jOptions>;
+
 type validationOptions = {
-  allowBooleanAttributes: boolean;
-  unpairedTags: string[];
+  /**
+   * Whether to allow attributes without value
+   * 
+   * Defaults to `false`
+   */
+  allowBooleanAttributes?: boolean;
+  
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
 };
-type validationOptionsOptional = Partial<validationOptions>;
 
 type XmlBuilderOptions = {
-  attributeNamePrefix: string;
-  attributesGroupName: false | string;
-  textNodeName: string;
-  ignoreAttributes: boolean;
-  cdataPropName: false | string;
-  commentPropName: false | string;
-  format: boolean;
-  indentBy: string;
-  arrayNodeName: string;
-  suppressEmptyNode: boolean;
-  suppressUnpairedNode: boolean;
-  suppressBooleanAttributes: boolean;
-  preserveOrder: boolean;
-  unpairedTags: string[];
-  stopNodes: string[];
-  tagValueProcessor: (name: string, value: unknown) => string;
-  attributeValueProcessor: (name: string, value: unknown) => string;
-  processEntities: boolean;
-  oneListGroup: boolean;
+  /**
+   * Give a prefix to the attribute name in the resulting JS object
+   * 
+   * Defaults to '@_'
+   */  
+  attributeNamePrefix?: string;
+
+  /**
+   * A name to group all attributes of a tag under, or `false` to disable
+   * 
+   * Defaults to `false`
+   */
+  attributesGroupName?: false | string;
+
+  /**
+   * The name of the next node in the resulting JS
+   * 
+   * Defaults to `#text`
+   */
+  textNodeName?: string;
+
+  /**
+   * Whether to ignore attributes when parsing
+   * 
+   * Defaults to `true`
+   */
+  ignoreAttributes?: boolean;
+
+  /**
+   * Give a property name to set CDATA values to instead of merging to tag's text value
+   * 
+   * Defaults to `false`
+   */
+  cdataPropName?: false | string;
+
+  /**
+   * If set, parse comments and set as this property
+   * 
+   * Defaults to `false`
+   */
+  commentPropName?: false | string;
+
+  /**
+   * Whether to make output pretty instead of single line
+   * 
+   * Defaults to `false`
+   */
+  format?: boolean;
+
+
+  /**
+   * If `format` is set to `true`, sets the indent string
+   * 
+   * Defaults to `  `
+   */
+  indentBy?: string;
+
+  /**
+   * Give a name to a top-level array
+   * 
+   * Defaults to `undefined`
+   */
+  arrayNodeName?: string;
+
+  /**
+   * Create empty tags for tags with no text value
+   * 
+   * Defaults to `false`
+   */
+  suppressEmptyNode?: boolean;
+
+  /**
+   * Suppress an unpaired tag
+   * 
+   * Defaults to `true`
+   */
+  suppressUnpairedNode?: boolean;
+
+  /**
+   * Don't put a value for boolean attributes
+   * 
+   * Defaults to `true`
+   */
+  suppressBooleanAttributes?: boolean;
+
+  /**
+   * Preserve the order of tags in resulting JS object
+   * 
+   * Defaults to `false`
+   */
+  preserveOrder?: boolean;
+
+  /**
+   * List of tags without closing tags
+   * 
+   * Defaults to `[]`
+   */
+  unpairedTags?: string[];
+
+  /**
+   * Nodes to stop parsing at
+   * 
+   * Defaults to `[]`
+   */
+  stopNodes?: string[];
+
+  /**
+   * Control how tag value should be parsed. Called only if tag value is not empty
+   * 
+   * @returns {undefined|null} `undefined` or `null` to set original value.
+   * @returns {unknown} 
+   * 
+   * 1. Different value or value with different data type to set new value.
+   * 2. Same value to set parsed value if `parseTagValue: true`.
+   * 
+   * Defaults to `(tagName, val, jPath, hasAttributes, isLeafNode) => val`
+   */
+  tagValueProcessor?: (name: string, value: unknown) => string;
+
+  /**
+   * Control how attribute value should be parsed
+   * 
+   * @param attrName 
+   * @param attrValue 
+   * @param jPath 
+   * @returns {undefined|null} `undefined` or `null` to set original value
+   * @returns {unknown}
+   * 
+   * Defaults to `(attrName, val, jPath) => val`
+   */
+  attributeValueProcessor?: (name: string, value: unknown) => string;
+
+  /**
+   * Whether to process default and DOCTYPE entities
+   * 
+   * Defaults to `true`
+   */
+  processEntities?: boolean;
+
+
+  oneListGroup?: boolean;
 };
-type XmlBuilderOptionsOptional = Partial<XmlBuilderOptions>;
 
 type ESchema = string | object | Array<string|object>;
 
@@ -89,8 +383,8 @@ type ValidationError = {
 };
 
 export class XMLParser {
-  constructor(options?: X2jOptionsOptional);
-  parse(xmlData: string | Buffer ,validationOptions?: validationOptionsOptional | boolean): any;
+  constructor(options?: X2jOptions);
+  parse(xmlData: string | Buffer ,validationOptions?: validationOptions | boolean): any;
   /**
    * Add Entity which is not by default supported by this library
    * @param entityIndentifier {string} Eg: 'ent' for &ent;
@@ -100,9 +394,9 @@ export class XMLParser {
 }
 
 export class XMLValidator{
-  static validate(  xmlData: string,  options?: validationOptionsOptional): true | ValidationError;
+  static validate(  xmlData: string,  options?: validationOptions): true | ValidationError;
 }
 export class XMLBuilder {
-  constructor(options?: XmlBuilderOptionsOptional);
+  constructor(options?: XmlBuilderOptions);
   build(jObj: any): any;
 }