diff --git a/src/index.rs b/src/index.rs
index 19f6f7c513..c09a50c31f 100644
--- a/src/index.rs
+++ b/src/index.rs
@@ -4,6 +4,7 @@ use {
       BlockHashValue, Entry, InscriptionEntry, InscriptionEntryValue, InscriptionIdValue,
       OutPointValue, SatPointValue, SatRange,
     },
+    index::block_index::BlockIndex,
     reorg::*,
     updater::Updater,
   },
@@ -13,7 +14,6 @@ use {
   bitcoincore_rpc::{json::GetBlockHeaderResult, Client},
   chrono::SubsecRound,
   indicatif::{ProgressBar, ProgressStyle},
-  itertools::Itertools,
   log::log_enabled,
   redb::{
     Database, MultimapTable, MultimapTableDefinition, ReadableMultimapTable, ReadableTable, Table,
@@ -23,6 +23,7 @@ use {
   std::io::{BufWriter, Read, Write},
 };
 
+pub mod block_index;
 mod entry;
 mod fetcher;
 mod reorg;
@@ -925,29 +926,12 @@ impl Index {
     Ok((inscriptions, prev, next, lowest, highest))
   }
 
-  pub(crate) fn get_inscriptions_in_block(&self, block_height: u64) -> Result<Vec<InscriptionId>> {
-    // This is a naive approach and will require optimization, but we don't have an index by block
-    let block_inscriptions = self
-      .database
-      .begin_read()?
-      .open_table(INSCRIPTION_ID_TO_INSCRIPTION_ENTRY)?
-      .iter()?
-      .filter_map(|result| match result {
-        Ok((key, entry_value)) => {
-          let entry = InscriptionEntry::load(entry_value.value());
-          if entry.height == block_height {
-            Some((InscriptionId::load(*key.value()), entry.number))
-          } else {
-            None
-          }
-        }
-        Err(_) => None,
-      })
-      .sorted_by_key(|&(_id, number)| number)
-      .map(|(id, _)| id)
-      .collect();
-
-    Ok(block_inscriptions)
+  pub(crate) fn get_inscriptions_in_block(
+    &self,
+    block_index: &BlockIndex,
+    block_height: u64,
+  ) -> Result<Vec<InscriptionId>> {
+    block_index.get_inscriptions_in_block(self, block_height)
   }
 
   pub(crate) fn get_feed_inscriptions(&self, n: usize) -> Result<Vec<(i64, InscriptionId)>> {
diff --git a/src/index/block_index.rs b/src/index/block_index.rs
new file mode 100644
index 0000000000..c036080f22
--- /dev/null
+++ b/src/index/block_index.rs
@@ -0,0 +1,201 @@
+use super::*;
+
+#[derive(Clone)]
+pub struct BlockIndex {
+  first_inscription_height: u64,
+  lowest_blessed_by_block: Vec<i64>,
+  lowest_cursed_by_block: Vec<i64>,
+  highest_indexed_blessed: i64,
+  lowest_indexed_cursed: i64,
+}
+
+impl BlockIndex {
+  pub(crate) fn new(index: &Index) -> Result<BlockIndex> {
+    Ok(BlockIndex {
+      first_inscription_height: index.options.first_inscription_height(),
+      lowest_blessed_by_block: Vec::new(),
+      lowest_cursed_by_block: Vec::new(),
+      highest_indexed_blessed: i64::MIN,
+      lowest_indexed_cursed: i64::MAX,
+    })
+  }
+
+  pub(crate) fn update(&mut self, index: &Index) -> Result {
+    let index_height = index.block_count()?;
+    let inscribed_block_count = index_height.saturating_sub(self.first_inscription_height);
+    let indexed_up_to: isize = self
+      .lowest_blessed_by_block
+      .len()
+      .try_into()
+      .unwrap_or(isize::MAX);
+
+    let gap = inscribed_block_count.try_into().unwrap_or(isize::MAX) - indexed_up_to;
+    if gap <= 0 {
+      return Ok(());
+    }
+
+    log::debug!(
+      "Updating block index for {} new blocks ({} to {})",
+      gap,
+      indexed_up_to,
+      inscribed_block_count
+    );
+
+    self
+      .lowest_blessed_by_block
+      .resize(usize::try_from(inscribed_block_count)?, i64::MAX);
+
+    self
+      .lowest_cursed_by_block
+      .resize(usize::try_from(inscribed_block_count)?, i64::MAX);
+
+    let rtx = index.database.begin_read()?;
+
+    // Use a more efficient approach for the initial indexing - since we have
+    // to traverse all inscriptions, it is most efficient to do so using one table.
+    if indexed_up_to == 0 {
+      for result in rtx
+        .open_table(INSCRIPTION_ID_TO_INSCRIPTION_ENTRY)?
+        .iter()?
+      {
+        let (_, entry) = result?;
+        let entry = InscriptionEntry::load(entry.value());
+        let height_index: usize = entry
+          .height
+          .try_into()
+          .unwrap_or(usize::MAX)
+          .saturating_sub(self.first_inscription_height.try_into().unwrap());
+
+        if entry.number < 0 {
+          self.lowest_cursed_by_block[height_index] =
+            cmp::min(self.lowest_cursed_by_block[height_index], entry.number);
+          self.lowest_indexed_cursed = cmp::min(self.lowest_indexed_cursed, entry.number);
+        } else {
+          self.lowest_blessed_by_block[height_index] =
+            cmp::min(self.lowest_blessed_by_block[height_index], entry.number);
+          self.highest_indexed_blessed = cmp::max(self.highest_indexed_blessed, entry.number);
+        }
+      }
+    } else {
+      // Use default approach where we iterate in order of inscription number
+      // so we can easily skip over already indexed inscriptions.
+      let mut prev_block_height = usize::MAX;
+
+      for result in rtx
+        .open_table(INSCRIPTION_NUMBER_TO_INSCRIPTION_ID)?
+        .iter()?
+      {
+        let (number, id) = result?;
+
+        if number.value() >= self.lowest_indexed_cursed
+          && number.value() <= self.highest_indexed_blessed
+        {
+          continue;
+        }
+
+        let inscription_id = InscriptionId::load(*id.value());
+
+        if let Some(entry) = index.get_inscription_entry(inscription_id)? {
+          let current_height = entry.height.try_into().unwrap_or(usize::MAX);
+
+          if prev_block_height != current_height {
+            prev_block_height = current_height;
+
+            if number.value() < 0 {
+              self.lowest_cursed_by_block[prev_block_height
+                .saturating_sub(usize::try_from(self.first_inscription_height)?)] = number.value();
+              self.lowest_indexed_cursed = cmp::min(self.lowest_indexed_cursed, number.value());
+            } else {
+              self.lowest_blessed_by_block[prev_block_height
+                .saturating_sub(usize::try_from(self.first_inscription_height)?)] = number.value();
+              self.highest_indexed_blessed = cmp::max(self.highest_indexed_blessed, number.value());
+            }
+          }
+        }
+      }
+    }
+
+    log::debug!(
+      "Updated block index for {} new blocks ({} to {})",
+      gap,
+      indexed_up_to,
+      inscribed_block_count
+    );
+
+    Ok(())
+  }
+
+  // Return all consecutively numbered inscriptions in the block at the given height, starting from the given number
+  fn get_inscriptions_in_block_from(
+    &self,
+    index: &Index,
+    block_height: u64,
+    from_number: i64,
+    cursed: bool,
+  ) -> Result<Vec<InscriptionId>> {
+    let mut block_inscriptions = Vec::new();
+
+    let rtx = index.database.begin_read()?;
+    let inscription_id_by_number = rtx.open_table(INSCRIPTION_NUMBER_TO_INSCRIPTION_ID)?;
+
+    let highest = if cursed {
+      -1
+    } else {
+      match inscription_id_by_number.iter()?.next_back() {
+        Some(Ok((number, _id))) => number.value(),
+        Some(Err(err)) => return Err(err.into()),
+        None => i64::MIN,
+      }
+    };
+
+    for number in from_number..=highest {
+      match inscription_id_by_number.get(number)? {
+        Some(inscription_id) => {
+          let inscription_id = InscriptionId::load(*inscription_id.value());
+          if let Some(entry) = index.get_inscription_entry(inscription_id)? {
+            if entry.height != block_height {
+              break;
+            }
+            block_inscriptions.push(inscription_id);
+          }
+        }
+        None => break,
+      }
+    }
+
+    Ok(block_inscriptions)
+  }
+
+  pub(crate) fn get_inscriptions_in_block(
+    &self,
+    index: &Index,
+    block_height: u64,
+  ) -> Result<Vec<InscriptionId>> {
+    if block_height >= index.block_count()? || block_height < self.first_inscription_height {
+      return Ok(Vec::new());
+    }
+    let lowest_cursed = self.lowest_cursed_by_block
+      [usize::try_from(block_height.saturating_sub(self.first_inscription_height))?];
+    let lowest_blessed = self.lowest_blessed_by_block
+      [usize::try_from(block_height.saturating_sub(self.first_inscription_height))?];
+
+    let mut inscriptions =
+      self.get_inscriptions_in_block_from(index, block_height, lowest_cursed, true)?;
+    inscriptions.extend(self.get_inscriptions_in_block_from(
+      index,
+      block_height,
+      lowest_blessed,
+      false,
+    )?);
+
+    log::debug!(
+      "Got {} inscriptions in block {} ({} - {})",
+      inscriptions.len(),
+      block_height,
+      lowest_cursed,
+      lowest_blessed
+    );
+
+    Ok(inscriptions)
+  }
+}
diff --git a/src/subcommand/server.rs b/src/subcommand/server.rs
index 8cc8f672a1..46b9fac786 100644
--- a/src/subcommand/server.rs
+++ b/src/subcommand/server.rs
@@ -5,6 +5,7 @@ use {
     error::{OptionExt, ServerError, ServerResult},
   },
   super::*,
+  crate::index::block_index::BlockIndex,
   crate::page_config::PageConfig,
   crate::templates::{
     BlockHtml, ClockSvg, HomeHtml, InputHtml, InscriptionHtml, InscriptionJson, InscriptionsHtml,
@@ -29,7 +30,7 @@ use {
     caches::DirCache,
     AcmeConfig,
   },
-  std::{cmp::Ordering, str, sync::Arc},
+  std::{cmp::Ordering, str, sync::Arc, sync::RwLock},
   tokio_stream::StreamExt,
   tower_http::{
     compression::CompressionLayer,
@@ -46,6 +47,10 @@ pub struct ServerConfig {
   pub is_json_api_enabled: bool,
 }
 
+struct BlockIndexState {
+  block_index: RwLock<BlockIndex>,
+}
+
 enum BlockQuery {
   Height(u64),
   Hash(BlockHash),
@@ -134,18 +139,38 @@ pub(crate) struct Server {
 impl Server {
   pub(crate) fn run(self, options: Options, index: Arc<Index>, handle: Handle) -> Result {
     Runtime::new()?.block_on(async {
+      let block_index_state = BlockIndexState {
+        block_index: RwLock::new(BlockIndex::new(&index)?),
+      };
+
+      let block_index_state = Arc::new(block_index_state);
+
       let index_clone = index.clone();
+      let block_index_clone = block_index_state.clone();
+
       let index_thread = thread::spawn(move || loop {
         if SHUTTING_DOWN.load(atomic::Ordering::Relaxed) {
           break;
         }
         if let Err(error) = index_clone.update() {
-          log::warn!("{error}");
+          log::warn!("Updating index: {error}");
+        }
+        if let Err(error) = block_index_clone
+          .block_index
+          .write()
+          .unwrap()
+          .update(&index_clone)
+        {
+          log::warn!("Updating block index: {error}");
         }
         thread::sleep(Duration::from_millis(5000));
       });
       INDEXER.lock().unwrap().replace(index_thread);
 
+      let server_config = Arc::new(ServerConfig {
+        is_json_api_enabled: index.is_json_api_enabled(),
+      });
+
       let config = options.load_config()?;
       let acme_domains = self.acme_domains()?;
 
@@ -154,10 +179,6 @@ impl Server {
         domain: acme_domains.first().cloned(),
       });
 
-      let server_config = Arc::new(ServerConfig {
-        is_json_api_enabled: index.is_json_api_enabled(),
-      });
-
       let router = Router::new()
         .route("/", get(Self::home))
         .route("/block/:query", get(Self::block))
@@ -193,6 +214,7 @@ impl Server {
         .layer(Extension(index))
         .layer(Extension(page_config))
         .layer(Extension(Arc::new(config)))
+        .layer(Extension(block_index_state))
         .layer(SetResponseHeaderLayer::if_not_present(
           header::CONTENT_SECURITY_POLICY,
           HeaderValue::from_static("default-src 'self'"),
@@ -1007,10 +1029,12 @@ impl Server {
   async fn inscriptions_in_block(
     Extension(page_config): Extension<Arc<PageConfig>>,
     Extension(index): Extension<Arc<Index>>,
+    Extension(block_index_state): Extension<Arc<BlockIndexState>>,
     Path(block_height): Path<u64>,
     accept_json: AcceptJson,
   ) -> ServerResult<Response> {
-    let inscriptions = index.get_inscriptions_in_block(block_height)?;
+    let inscriptions = index
+      .get_inscriptions_in_block(&block_index_state.block_index.read().unwrap(), block_height)?;
     Ok(if accept_json.0 {
       Json(InscriptionsJson::new(inscriptions, None, None, None, None)).into_response()
     } else {
diff --git a/tests/json_api.rs b/tests/json_api.rs
index 893ede9327..893d7c7673 100644
--- a/tests/json_api.rs
+++ b/tests/json_api.rs
@@ -321,7 +321,15 @@ fn get_inscriptions_in_block() {
   }
   rpc_server.mine_blocks(1);
 
-  let server = TestServer::spawn_with_args(&rpc_server, &["--index-sats", "--enable-json-api"]);
+  let server = TestServer::spawn_with_args(
+    &rpc_server,
+    &[
+      "--index-sats",
+      "--enable-json-api",
+      "--first-inscription-height",
+      "0",
+    ],
+  );
 
   // get all inscriptions from block 11
   let response = server.json_request(format!("/inscriptions/block/{}", 11));
@@ -330,7 +338,6 @@ fn get_inscriptions_in_block() {
   let inscriptions_json: InscriptionsJson =
     serde_json::from_str(&response.text().unwrap()).unwrap();
 
-  assert_eq!(inscriptions_json.inscriptions.len(), 3);
   pretty_assert_eq!(
     inscriptions_json.inscriptions,
     vec![