diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index fdd497bbac..db3eb869ac 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -1196,14 +1196,14 @@ impl Inner {
     // a @types/node package and now's a good time to do that anyway
     self.refresh_npm_specifiers().await;
 
-    self.project_changed(&[], true).await;
+    self.project_changed([], true);
   }
 
   fn shutdown(&self) -> LspResult<()> {
     Ok(())
   }
 
-  async fn did_open(
+  fn did_open(
     &mut self,
     specifier: &ModuleSpecifier,
     params: DidOpenTextDocumentParams,
@@ -1231,9 +1231,7 @@ impl Inner {
       params.text_document.language_id.parse().unwrap(),
       params.text_document.text.into(),
     );
-    self
-      .project_changed(&[(document.specifier(), ChangeKind::Opened)], false)
-      .await;
+    self.project_changed([(document.specifier(), ChangeKind::Opened)], false);
 
     self.performance.measure(mark);
     document
@@ -1251,12 +1249,10 @@ impl Inner {
     ) {
       Ok(document) => {
         if document.is_diagnosable() {
-          self
-            .project_changed(
-              &[(document.specifier(), ChangeKind::Modified)],
-              false,
-            )
-            .await;
+          self.project_changed(
+            [(document.specifier(), ChangeKind::Modified)],
+            false,
+          );
           self.refresh_npm_specifiers().await;
           self.diagnostics_server.invalidate(&[specifier]);
           self.send_diagnostics_update();
@@ -1307,9 +1303,7 @@ impl Inner {
     if let Err(err) = self.documents.close(&specifier) {
       error!("{:#}", err);
     }
-    self
-      .project_changed(&[(&specifier, ChangeKind::Closed)], false)
-      .await;
+    self.project_changed([(&specifier, ChangeKind::Closed)], false);
     self.performance.measure(mark);
   }
 
@@ -1423,15 +1417,10 @@ impl Inner {
       self.recreate_npm_services_if_necessary().await;
       self.refresh_documents_config().await;
       self.diagnostics_server.invalidate_all();
-      self
-        .project_changed(
-          &changes
-            .iter()
-            .map(|(s, _)| (s, ChangeKind::Modified))
-            .collect::<Vec<_>>(),
-          false,
-        )
-        .await;
+      self.project_changed(
+        changes.iter().map(|(s, _)| (s, ChangeKind::Modified)),
+        false,
+      );
       self.ts_server.cleanup_semantic_cache(self.snapshot()).await;
       self.send_diagnostics_update();
       self.send_testing_update();
@@ -3004,16 +2993,17 @@ impl Inner {
     Ok(maybe_symbol_information)
   }
 
-  async fn project_changed(
+  fn project_changed<'a>(
     &mut self,
-    modified_scripts: &[(&ModuleSpecifier, ChangeKind)],
+    modified_scripts: impl IntoIterator<Item = (&'a ModuleSpecifier, ChangeKind)>,
     config_changed: bool,
   ) {
     self.project_version += 1; // increment before getting the snapshot
-    self
-      .ts_server
-      .project_changed(self.snapshot(), modified_scripts, config_changed)
-      .await;
+    self.ts_server.project_changed(
+      self.snapshot(),
+      modified_scripts,
+      config_changed,
+    );
   }
 
   fn send_diagnostics_update(&self) {
@@ -3221,7 +3211,7 @@ impl tower_lsp::LanguageServer for LanguageServer {
     let specifier = inner
       .url_map
       .normalize_url(&params.text_document.uri, LspUrlKind::File);
-    let document = inner.did_open(&specifier, params).await;
+    let document = inner.did_open(&specifier, params);
     if document.is_diagnosable() {
       inner.refresh_npm_specifiers().await;
       inner.diagnostics_server.invalidate(&[specifier]);
@@ -3561,7 +3551,7 @@ impl Inner {
     // the language server for TypeScript (as it might hold to some stale
     // documents).
     self.diagnostics_server.invalidate_all();
-    self.project_changed(&[], false).await;
+    self.project_changed([], false);
     self.ts_server.cleanup_semantic_cache(self.snapshot()).await;
     self.send_diagnostics_update();
     self.send_testing_update();
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index 2873ba703b..4cb93e8024 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -107,6 +107,7 @@ type Request = (
   Arc<StateSnapshot>,
   oneshot::Sender<Result<String, AnyError>>,
   CancellationToken,
+  Option<Value>,
 );
 
 #[derive(Debug, Clone, Copy, Serialize_repr)]
@@ -224,6 +225,7 @@ pub struct TsServer {
   receiver: Mutex<Option<mpsc::UnboundedReceiver<Request>>>,
   specifier_map: Arc<TscSpecifierMap>,
   inspector_server: Mutex<Option<Arc<InspectorServer>>>,
+  pending_change: Mutex<Option<PendingChange>>,
 }
 
 impl std::fmt::Debug for TsServer {
@@ -256,6 +258,47 @@ impl Serialize for ChangeKind {
   }
 }
 
+pub struct PendingChange {
+  pub modified_scripts: Vec<(String, ChangeKind)>,
+  pub project_version: usize,
+  pub config_changed: bool,
+}
+
+impl PendingChange {
+  fn to_json(&self) -> Value {
+    json!([
+      self.modified_scripts,
+      self.project_version,
+      self.config_changed,
+    ])
+  }
+
+  fn coalesce(
+    &mut self,
+    new_version: usize,
+    modified_scripts: Vec<(String, ChangeKind)>,
+    config_changed: bool,
+  ) {
+    self.project_version = self.project_version.max(new_version);
+    self.config_changed |= config_changed;
+    for (spec, new) in modified_scripts {
+      if let Some((_, current)) =
+        self.modified_scripts.iter_mut().find(|(s, _)| s == &spec)
+      {
+        match (*current, new) {
+          (_, ChangeKind::Closed) => {
+            *current = ChangeKind::Closed;
+          }
+          (ChangeKind::Opened, ChangeKind::Modified) => {
+            *current = ChangeKind::Modified;
+          }
+          _ => {}
+        }
+      }
+    }
+  }
+}
+
 impl TsServer {
   pub fn new(performance: Arc<Performance>, cache: Arc<dyn HttpCache>) -> Self {
     let (tx, request_rx) = mpsc::unbounded_channel::<Request>();
@@ -266,6 +309,7 @@ impl TsServer {
       receiver: Mutex::new(Some(request_rx)),
       specifier_map: Arc::new(TscSpecifierMap::new()),
       inspector_server: Mutex::new(None),
+      pending_change: Mutex::new(None),
     }
   }
 
@@ -302,30 +346,33 @@ impl TsServer {
     Ok(())
   }
 
-  pub async fn project_changed(
+  pub fn project_changed<'a>(
     &self,
     snapshot: Arc<StateSnapshot>,
-    modified_scripts: &[(&ModuleSpecifier, ChangeKind)],
+    modified_scripts: impl IntoIterator<Item = (&'a ModuleSpecifier, ChangeKind)>,
     config_changed: bool,
   ) {
     let modified_scripts = modified_scripts
-      .iter()
+      .into_iter()
       .map(|(spec, change)| (self.specifier_map.denormalize(spec), change))
       .collect::<Vec<_>>();
-    let req = TscRequest {
-      method: "$projectChanged",
-      args: json!(
-        [modified_scripts, snapshot.project_version, config_changed,]
-      ),
-    };
-    self
-      .request::<()>(snapshot, req)
-      .await
-      .map_err(|err| {
-        log::error!("Failed to request to tsserver {}", err);
-        LspError::invalid_request()
-      })
-      .ok();
+    match &mut *self.pending_change.lock() {
+      Some(pending_change) => {
+        pending_change.coalesce(
+          snapshot.project_version,
+          modified_scripts,
+          config_changed,
+        );
+      }
+      pending => {
+        let pending_change = PendingChange {
+          modified_scripts,
+          project_version: snapshot.project_version,
+          config_changed,
+        };
+        *pending = Some(pending_change);
+      }
+    }
   }
 
   pub async fn get_diagnostics(
@@ -1069,7 +1116,12 @@ impl TsServer {
     let token = token.child_token();
     let droppable_token = DroppableToken(token.clone());
     let (tx, rx) = oneshot::channel::<Result<String, AnyError>>();
-    if self.sender.send((req, snapshot, tx, token)).is_err() {
+    let change = self.pending_change.lock().take();
+    if self
+      .sender
+      .send((req, snapshot, tx, token, change.map(|c| c.to_json())))
+      .is_err()
+    {
       return Err(anyhow!("failed to send request to tsc thread"));
     }
     let value = rx.await??;
@@ -4245,8 +4297,8 @@ fn run_tsc_thread(
       tokio::select! {
         biased;
         (maybe_request, mut tsc_runtime) = async { (request_rx.recv().await, tsc_runtime.lock().await) } => {
-          if let Some((req, state_snapshot, tx, token)) = maybe_request {
-            let value = request(&mut tsc_runtime, state_snapshot, req, token.clone());
+          if let Some((req, state_snapshot, tx, token, pending_change)) = maybe_request {
+            let value = request(&mut tsc_runtime, state_snapshot, req, pending_change, token.clone());
             request_signal_tx.send(()).unwrap();
             let was_sent = tx.send(value).is_ok();
             // Don't print the send error if the token is cancelled, it's expected
@@ -4664,6 +4716,7 @@ fn request(
   runtime: &mut JsRuntime,
   state_snapshot: Arc<StateSnapshot>,
   request: TscRequest,
+  change: Option<Value>,
   token: CancellationToken,
 ) -> Result<String, AnyError> {
   if token.is_cancelled() {
@@ -4688,8 +4741,10 @@ fn request(
     "Internal error: expected args to be array"
   );
   let request_src = format!(
-    "globalThis.serverRequest({id}, \"{}\", {});",
-    request.method, &request.args
+    "globalThis.serverRequest({id}, \"{}\", {}, {});",
+    request.method,
+    &request.args,
+    change.unwrap_or_default()
   );
   runtime.execute_script(located_script_name!(), request_src)?;
 
@@ -5221,13 +5276,11 @@ mod tests {
         ..snapshot.as_ref().clone()
       })
     };
-    ts_server
-      .project_changed(
-        snapshot.clone(),
-        &[(&specifier_dep, ChangeKind::Opened)],
-        false,
-      )
-      .await;
+    ts_server.project_changed(
+      snapshot.clone(),
+      [(&specifier_dep, ChangeKind::Opened)],
+      false,
+    );
     let specifier = resolve_url("file:///a.ts").unwrap();
     let diagnostics = ts_server
       .get_diagnostics(snapshot.clone(), vec![specifier], Default::default())
diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index 836d81f87e..c2c9a88d57 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -542,7 +542,7 @@ delete Object.prototype.__proto__;
     }
   }
 
-  /** @type {ts.LanguageService} */
+  /** @type {ts.LanguageService & { [k:string]: any }} */
   let languageService;
 
   /** An object literal of the incremental compiler host, which provides the
@@ -1073,42 +1073,43 @@ delete Object.prototype.__proto__;
     ops.op_respond(JSON.stringify(data));
   }
 
-  function serverRequest(id, method, args) {
+  /**
+   * @param {number} id
+   * @param {string} method
+   * @param {any[]} args
+   * @param {[[string, number][], number, boolean] | null} maybeChange
+   */
+  function serverRequest(id, method, args, maybeChange) {
     if (logDebug) {
-      debug(`serverRequest()`, id, method, args);
+      debug(`serverRequest()`, id, method, args, maybeChange);
     }
     lastRequestMethod = method;
-    switch (method) {
-      case "$projectChanged": {
-        /** @type {[string, number][]} */
-        const changedScripts = args[0];
-        /** @type {number} */
-        const newProjectVersion = args[1];
-        /** @type {boolean} */
-        const configChanged = args[2];
+    if (maybeChange !== null) {
+      const changedScripts = maybeChange[0];
+      const newProjectVersion = maybeChange[1];
+      const configChanged = maybeChange[2];
 
-        if (configChanged) {
-          tsConfigCache = null;
-          isNodeSourceFileCache.clear();
-        }
-
-        projectVersionCache = newProjectVersion;
-
-        let opened = false;
-        for (const { 0: script, 1: changeKind } of changedScripts) {
-          if (changeKind == ChangeKind.Opened) {
-            opened = true;
-          }
-          scriptVersionCache.delete(script);
-          sourceTextCache.delete(script);
-        }
-
-        if (configChanged || opened) {
-          scriptFileNamesCache = undefined;
-        }
-
-        return respond(id);
+      if (configChanged) {
+        tsConfigCache = null;
+        isNodeSourceFileCache.clear();
       }
+
+      projectVersionCache = newProjectVersion;
+
+      let opened = false;
+      for (const { 0: script, 1: changeKind } of changedScripts) {
+        if (changeKind == ChangeKind.Opened) {
+          opened = true;
+        }
+        scriptVersionCache.delete(script);
+        sourceTextCache.delete(script);
+      }
+
+      if (configChanged || opened) {
+        scriptFileNamesCache = undefined;
+      }
+    }
+    switch (method) {
       case "$getSupportedCodeFixes": {
         return respond(
           id,
diff --git a/tests/integration/lsp_tests.rs b/tests/integration/lsp_tests.rs
index 76d6e22e10..3554f303a8 100644
--- a/tests/integration/lsp_tests.rs
+++ b/tests/integration/lsp_tests.rs
@@ -9044,7 +9044,6 @@ fn lsp_performance() {
       "tsc.host.$getAssets",
       "tsc.host.$getDiagnostics",
       "tsc.host.$getSupportedCodeFixes",
-      "tsc.host.$projectChanged",
       "tsc.host.getQuickInfoAtPosition",
       "tsc.op.op_is_node_file",
       "tsc.op.op_load",
@@ -9052,7 +9051,6 @@ fn lsp_performance() {
       "tsc.op.op_ts_config",
       "tsc.request.$getAssets",
       "tsc.request.$getSupportedCodeFixes",
-      "tsc.request.$projectChanged",
       "tsc.request.getQuickInfoAtPosition",
     ]
   );