diff --git a/analysis/bin/main.ml b/analysis/bin/main.ml
index 7df0d0c6c..cdc8c0b29 100644
--- a/analysis/bin/main.ml
+++ b/analysis/bin/main.ml
@@ -111,10 +111,22 @@ let main () =
   in
   match args with
   | [_; "cache-project"; rootPath] -> (
+    Cfg.useProjectConfigCache := false;
     let uri = Uri.fromPath rootPath in
     match Packages.getPackage ~uri with
     | Some package -> Cache.cacheProject package
-    | None -> ())
+    | None -> print_endline "\"ERR\"")
+  | [_; "cache-delete"; rootPath] -> (
+    Cfg.useProjectConfigCache := false;
+    let uri = Uri.fromPath rootPath in
+    match Packages.findRoot ~uri (Hashtbl.create 0) with
+    | Some (`Bs rootPath) -> (
+      match BuildSystem.getLibBs rootPath with
+      | None -> print_endline "\"ERR\""
+      | Some libBs ->
+        Cache.deleteCache (Cache.targetFileFromLibBs libBs);
+        print_endline "\"OK\"")
+    | _ -> print_endline "\"ERR: Did not find root \"")
   | [_; "completion"; path; line; col; currentFile] ->
     printHeaderInfo path line col;
     Commands.completion ~debug ~path
diff --git a/analysis/src/Cache.ml b/analysis/src/Cache.ml
index 62dd8b921..90463408e 100644
--- a/analysis/src/Cache.ml
+++ b/analysis/src/Cache.ml
@@ -21,6 +21,8 @@ let readCache filename =
     with _ -> None
   else None
 
+let deleteCache filename = try Sys.remove filename with _ -> ()
+
 let targetFileFromLibBs libBs = Filename.concat libBs ".project-files-cache"
 
 let cacheProject (package : package) =
@@ -32,8 +34,8 @@ let cacheProject (package : package) =
     }
   in
   match BuildSystem.getLibBs package.rootPath with
-  | None -> ()
+  | None -> print_endline "\"ERR\""
   | Some libBs ->
     let targetFile = targetFileFromLibBs libBs in
     writeCache targetFile cached;
-    print_endline "OK"
+    print_endline "\"OK\""
diff --git a/analysis/src/Packages.ml b/analysis/src/Packages.ml
index cd2d3b528..59021ce9e 100644
--- a/analysis/src/Packages.ml
+++ b/analysis/src/Packages.ml
@@ -231,7 +231,7 @@ let findRoot ~uri packagesByRoot =
       let parent = Filename.dirname path in
       if parent = path then (* reached root *) None else loop parent
   in
-  loop (Filename.dirname path)
+  loop (if Sys.is_directory path then path else Filename.dirname path)
 
 let getPackage ~uri =
   let open SharedTypes in
diff --git a/client/src/extension.ts b/client/src/extension.ts
index 08bcfd1fa..350d88718 100644
--- a/client/src/extension.ts
+++ b/client/src/extension.ts
@@ -341,7 +341,8 @@ export function activate(context: ExtensionContext) {
         affectsConfiguration("rescript.settings.inlayHints") ||
         affectsConfiguration("rescript.settings.codeLens") ||
         affectsConfiguration("rescript.settings.signatureHelp") ||
-        affectsConfiguration("rescript.settings.incrementalTypechecking")
+        affectsConfiguration("rescript.settings.incrementalTypechecking") ||
+        affectsConfiguration("rescript.settings.cache")
       ) {
         commands.executeCommand("rescript-vscode.restart_language_server");
       } else {
diff --git a/package.json b/package.json
index 82356a3b0..507f8d773 100644
--- a/package.json
+++ b/package.json
@@ -192,6 +192,11 @@
           "default": false,
           "description": "(debug) Enable debug logging (ends up in the extension output)."
         },
+        "rescript.settings.cache.projectConfig.enabled": {
+          "type": "boolean",
+          "default": false,
+          "description": "(beta/experimental) Enable project config caching. Can speed up latency dramatically."
+        },
         "rescript.settings.binaryPath": {
           "type": [
             "string",
diff --git a/server/src/config.ts b/server/src/config.ts
index 9949d6bde..567f05585 100644
--- a/server/src/config.ts
+++ b/server/src/config.ts
@@ -21,6 +21,11 @@ export interface extensionConfiguration {
     acrossFiles?: boolean;
     debugLogging?: boolean;
   };
+  cache?: {
+    projectConfig?: {
+      enabled?: boolean;
+    };
+  };
 }
 
 // All values here are temporary, and will be overridden as the server is
@@ -43,7 +48,12 @@ let config: { extensionConfiguration: extensionConfiguration } = {
     incrementalTypechecking: {
       enabled: false,
       acrossFiles: false,
-      debugLogging: true,
+      debugLogging: false,
+    },
+    cache: {
+      projectConfig: {
+        enabled: false,
+      },
     },
   },
 };
diff --git a/server/src/constants.ts b/server/src/constants.ts
index fd6e29472..a08525523 100644
--- a/server/src/constants.ts
+++ b/server/src/constants.ts
@@ -44,6 +44,7 @@ export let bsconfigPartialPath = "bsconfig.json";
 export let rescriptJsonPartialPath = "rescript.json";
 export let compilerDirPartialPath = path.join("lib", "bs");
 export let compilerLogPartialPath = path.join("lib", "bs", ".compiler.log");
+export let buildNinjaPartialPath = path.join("lib", "bs", "build.ninja");
 export let resExt = ".res";
 export let resiExt = ".resi";
 export let cmiExt = ".cmi";
diff --git a/server/src/server.ts b/server/src/server.ts
index cfef4f572..42e09f42c 100644
--- a/server/src/server.ts
+++ b/server/src/server.ts
@@ -205,20 +205,49 @@ let sendCompilationFinishedMessage = () => {
   send(notification);
 };
 
+let debug = false;
+
+let syncProjectConfigCache = (rootPath: string) => {
+  try {
+    if (debug) console.log("syncing project config cache for " + rootPath);
+    utils.runAnalysisAfterSanityCheck(rootPath, ["cache-project", rootPath]);
+    if (debug) console.log("OK - synced project config cache for " + rootPath);
+  } catch (e) {
+    if (debug) console.error(e);
+  }
+};
+
+let deleteProjectConfigCache = (rootPath: string) => {
+  try {
+    if (debug) console.log("deleting project config cache for " + rootPath);
+    utils.runAnalysisAfterSanityCheck(rootPath, ["cache-delete", rootPath]);
+    if (debug) console.log("OK - deleted project config cache for " + rootPath);
+  } catch (e) {
+    if (debug) console.error(e);
+  }
+};
+
 let compilerLogsWatcher = chokidar
   .watch([], {
     awaitWriteFinish: {
       stabilityThreshold: 1,
     },
   })
-  .on("all", (_e, _changedPath) => {
-    sendUpdatedDiagnostics();
-    sendCompilationFinishedMessage();
-    if (config.extensionConfiguration.inlayHints?.enable === true) {
-      sendInlayHintsRefresh();
-    }
-    if (config.extensionConfiguration.codeLens === true) {
-      sendCodeLensRefresh();
+  .on("all", (_e, changedPath) => {
+    if (changedPath.includes("build.ninja")) {
+      let projectRoot = utils.findProjectRootOfFile(changedPath);
+      if (projectRoot != null) {
+        syncProjectConfigCache(projectRoot);
+      }
+    } else {
+      sendUpdatedDiagnostics();
+      sendCompilationFinishedMessage();
+      if (config.extensionConfiguration.inlayHints?.enable === true) {
+        sendInlayHintsRefresh();
+      }
+      if (config.extensionConfiguration.codeLens === true) {
+        sendCodeLensRefresh();
+      }
     }
   });
 let stopWatchingCompilerLog = () => {
@@ -257,6 +286,14 @@ let openedFile = (fileUri: string, fileContent: string) => {
       compilerLogsWatcher.add(
         path.join(projectRootPath, c.compilerLogPartialPath)
       );
+      if (
+        config.extensionConfiguration.cache?.projectConfig?.enabled === true
+      ) {
+        compilerLogsWatcher.add(
+          path.join(projectRootPath, c.buildNinjaPartialPath)
+        );
+        syncProjectConfigCache(projectRootPath);
+      }
     }
     let root = projectsFiles.get(projectRootPath)!;
     root.openFiles.add(filePath);
@@ -335,6 +372,10 @@ let closedFile = (fileUri: string) => {
         compilerLogsWatcher.unwatch(
           path.join(projectRootPath, c.compilerLogPartialPath)
         );
+        compilerLogsWatcher.unwatch(
+          path.join(projectRootPath, c.buildNinjaPartialPath)
+        );
+        deleteProjectConfigCache(projectRootPath);
         deleteProjectDiagnostics(projectRootPath);
         if (root.bsbWatcherByEditor !== null) {
           root.bsbWatcherByEditor.kill();
diff --git a/server/src/utils.ts b/server/src/utils.ts
index 8f952ffff..0fbe42a9c 100644
--- a/server/src/utils.ts
+++ b/server/src/utils.ts
@@ -190,6 +190,10 @@ export let runAnalysisAfterSanityCheck = (
         config.extensionConfiguration.incrementalTypechecking?.enabled === true
           ? "true"
           : undefined,
+      RESCRIPT_PROJECT_CONFIG_CACHE:
+        config.extensionConfiguration.cache?.projectConfig?.enabled === true
+          ? "true"
+          : undefined,
     },
   };
   let stdout = "";