diff --git a/server/src/buildSchema.ts b/server/src/buildSchema.ts
new file mode 100644
index 000000000..99c7cfe4f
--- /dev/null
+++ b/server/src/buildSchema.ts
@@ -0,0 +1,33 @@
+// This file has been generated from https://raw.githubusercontent.com/rescript-lang/rescript-compiler/master/docs/docson/build-schema.json
+// with https://app.quicktype.io/ and stripped down to what we actually need for the extension.
+
+export interface BuildSchema {
+  name: string;
+  namespace?: boolean | string;
+  "package-specs"?:
+    | Array<ModuleFormat | ModuleFormatObject>
+    | ModuleFormat
+    | ModuleFormatObject;
+  suffix?: SuffixSpec;
+}
+
+export enum ModuleFormat {
+  Commonjs = "commonjs",
+  Es6 = "es6",
+  Es6Global = "es6-global",
+}
+
+export interface ModuleFormatObject {
+  "in-source"?: boolean;
+  module: ModuleFormat;
+  suffix?: SuffixSpec;
+}
+
+export enum SuffixSpec {
+  BsCjs = ".bs.cjs",
+  BsJS = ".bs.js",
+  BsMjs = ".bs.mjs",
+  Cjs = ".cjs",
+  JS = ".js",
+  Mjs = ".mjs",
+}
diff --git a/server/src/constants.ts b/server/src/constants.ts
index 1bc0bd55b..0709089ab 100644
--- a/server/src/constants.ts
+++ b/server/src/constants.ts
@@ -1,4 +1,5 @@
 import * as path from "path";
+import { ModuleFormat } from "./buildSchema";
 
 export let platformDir =
   process.arch == "arm64" ? process.platform + process.arch : process.platform;
@@ -49,7 +50,7 @@ export let cmiExt = ".cmi";
 export let startBuildAction = "Start Build";
 
 // bsconfig defaults according configuration schema (https://rescript-lang.org/docs/manual/latest/build-configuration-schema)
-export let bsconfigModuleDefault = "commonjs";
+export let bsconfigModuleDefault = ModuleFormat.Commonjs;
 export let bsconfigSuffixDefault = ".js";
 
 export let configurationRequestId = "rescript_configuration_request";
diff --git a/server/src/lookup.ts b/server/src/lookup.ts
new file mode 100644
index 000000000..62c0535ec
--- /dev/null
+++ b/server/src/lookup.ts
@@ -0,0 +1,150 @@
+import * as fs from "fs";
+import * as path from "path";
+import * as p from "vscode-languageserver-protocol";
+
+import { BuildSchema, ModuleFormat, ModuleFormatObject } from "./buildSchema";
+import * as c from "./constants";
+
+const getCompiledFolderName = (moduleFormat: ModuleFormat): string => {
+  switch (moduleFormat) {
+    case "es6":
+      return "es6";
+    case "es6-global":
+      return "es6_global";
+    case "commonjs":
+    default:
+      return "js";
+  }
+};
+
+export const replaceFileExtension = (filePath: string, ext: string): string => {
+  let name = path.basename(filePath, path.extname(filePath));
+  return path.format({ dir: path.dirname(filePath), name, ext });
+};
+
+// Check if filePartialPath exists at directory and return the joined path,
+// otherwise recursively check parent directories for it.
+export const findFilePathFromProjectRoot = (
+  directory: p.DocumentUri | null, // This must be a directory and not a file!
+  filePartialPath: string
+): null | p.DocumentUri => {
+  if (directory == null) {
+    return null;
+  }
+
+  let filePath: p.DocumentUri = path.join(directory, filePartialPath);
+  if (fs.existsSync(filePath)) {
+    return filePath;
+  }
+
+  let parentDir: p.DocumentUri = path.dirname(directory);
+  if (parentDir === directory) {
+    // reached the top
+    return null;
+  }
+
+  return findFilePathFromProjectRoot(parentDir, filePartialPath);
+};
+
+export const readBsConfig = (projDir: p.DocumentUri): BuildSchema | null => {
+  try {
+    let bsconfigFile = fs.readFileSync(
+      path.join(projDir, c.bsconfigPartialPath),
+      { encoding: "utf-8" }
+    );
+
+    let result: BuildSchema = JSON.parse(bsconfigFile);
+    return result;
+  } catch (e) {
+    return null;
+  }
+};
+
+// Collect data from bsconfig to be able to find out the correct path of
+// the compiled JS artifacts.
+export const getSuffixAndPathFragmentFromBsconfig = (bsconfig: BuildSchema) => {
+  let pkgSpecs = bsconfig["package-specs"];
+  let pathFragment = "";
+  let module = c.bsconfigModuleDefault;
+  let moduleFormatObj: ModuleFormatObject = { module: module };
+  let suffix = c.bsconfigSuffixDefault;
+
+  if (pkgSpecs) {
+    if (
+      !Array.isArray(pkgSpecs) &&
+      typeof pkgSpecs !== "string" &&
+      pkgSpecs.module
+    ) {
+      moduleFormatObj = pkgSpecs;
+    } else if (typeof pkgSpecs === "string") {
+      module = pkgSpecs;
+    } else if (Array.isArray(pkgSpecs) && pkgSpecs[0]) {
+      if (typeof pkgSpecs[0] === "string") {
+        module = pkgSpecs[0];
+      } else {
+        moduleFormatObj = pkgSpecs[0];
+      }
+    }
+  }
+
+  if (moduleFormatObj["module"]) {
+    module = moduleFormatObj["module"];
+  }
+
+  if (!moduleFormatObj["in-source"]) {
+    pathFragment = "lib/" + getCompiledFolderName(module);
+  }
+
+  if (moduleFormatObj.suffix) {
+    suffix = moduleFormatObj.suffix;
+  } else if (bsconfig.suffix) {
+    suffix = bsconfig.suffix;
+  }
+
+  return [suffix, pathFragment];
+};
+
+export const getFilenameFromBsconfig = (
+  projDir: string,
+  partialFilePath: string
+): string | null => {
+  let bsconfig = readBsConfig(projDir);
+
+  if (!bsconfig) {
+    return null;
+  }
+
+  let [suffix, pathFragment] = getSuffixAndPathFragmentFromBsconfig(bsconfig);
+
+  let compiledPartialPath = replaceFileExtension(partialFilePath, suffix);
+
+  return path.join(projDir, pathFragment, compiledPartialPath);
+};
+
+// Monorepo helpers
+export const getFilenameFromRootBsconfig = (
+  projDir: string,
+  partialFilePath: string
+): string | null => {
+  let rootBsConfigPath = findFilePathFromProjectRoot(
+    path.join("..", projDir),
+    c.bsconfigPartialPath
+  );
+
+  if (!rootBsConfigPath) {
+    return null;
+  }
+
+  let rootBsconfig = readBsConfig(path.dirname(rootBsConfigPath));
+
+  if (!rootBsconfig) {
+    return null;
+  }
+
+  let [suffix, pathFragment] =
+    getSuffixAndPathFragmentFromBsconfig(rootBsconfig);
+
+  let compiledPartialPath = replaceFileExtension(partialFilePath, suffix);
+
+  return path.join(projDir, pathFragment, compiledPartialPath);
+};
diff --git a/server/src/server.ts b/server/src/server.ts
index 7a1e374ea..2fb305f59 100644
--- a/server/src/server.ts
+++ b/server/src/server.ts
@@ -15,6 +15,7 @@ import {
   CodeLensParams,
   SignatureHelpParams,
 } from "vscode-languageserver-protocol";
+import * as lookup from "./lookup";
 import * as utils from "./utils";
 import * as codeActions from "./codeActions";
 import * as c from "./constants";
@@ -102,7 +103,10 @@ let send: (msg: p.Message) => void = (_) => {};
 
 let findRescriptBinary = (projectRootPath: p.DocumentUri | null) =>
   extensionConfiguration.binaryPath == null
-    ? utils.findFilePathFromProjectRoot(projectRootPath, path.join(c.nodeModulesBinDir, c.rescriptBinName))
+    ? lookup.findFilePathFromProjectRoot(
+        projectRootPath,
+        path.join(c.nodeModulesBinDir, c.rescriptBinName)
+      )
     : utils.findBinary(extensionConfiguration.binaryPath, c.rescriptBinName);
 
 let findPlatformPath = (projectRootPath: p.DocumentUri | null) => {
@@ -110,12 +114,15 @@ let findPlatformPath = (projectRootPath: p.DocumentUri | null) => {
     return extensionConfiguration.platformPath;
   }
 
-  let rescriptDir = utils.findFilePathFromProjectRoot(projectRootPath, path.join("node_modules", "rescript"));
+  let rescriptDir = lookup.findFilePathFromProjectRoot(
+    projectRootPath,
+    path.join("node_modules", "rescript")
+  );
   if (rescriptDir == null) {
     return null;
   }
 
-  let platformPath = path.join(rescriptDir, c.platformDir)
+  let platformPath = path.join(rescriptDir, c.platformDir);
 
   // Workaround for darwinarm64 which has no folder yet in ReScript <= 9.1.4
   if (
@@ -127,10 +134,10 @@ let findPlatformPath = (projectRootPath: p.DocumentUri | null) => {
   }
 
   return platformPath;
-}
+};
 
 let findBscExeBinary = (projectRootPath: p.DocumentUri | null) =>
-  utils.findBinary(findPlatformPath(projectRootPath), c.bscExeName)
+  utils.findBinary(findPlatformPath(projectRootPath), c.bscExeName);
 
 interface CreateInterfaceRequestParams {
   uri: string;
@@ -941,7 +948,7 @@ function createInterface(msg: p.RequestMessage): p.Message {
   let result = typeof response.result === "string" ? response.result : "";
 
   try {
-    let resiPath = utils.replaceFileExtension(filePath, c.resiExt);
+    let resiPath = lookup.replaceFileExtension(filePath, c.resiExt);
     fs.writeFileSync(resiPath, result, { encoding: "utf-8" });
     let response: p.ResponseMessage = {
       jsonrpc: c.jsonrpcVersion,
diff --git a/server/src/utils.ts b/server/src/utils.ts
index 5360e10ec..1535c7050 100644
--- a/server/src/utils.ts
+++ b/server/src/utils.ts
@@ -1,5 +1,3 @@
-import * as c from "./constants";
-import * as codeActions from "./codeActions";
 import * as childProcess from "child_process";
 import * as p from "vscode-languageserver-protocol";
 import * as path from "path";
@@ -11,6 +9,10 @@ import {
 import fs from "fs";
 import * as os from "os";
 
+import * as codeActions from "./codeActions";
+import * as c from "./constants";
+import * as lookup from "./lookup";
+
 let tempFilePrefix = "rescript_format_file_" + process.pid + "_";
 let tempFileId = 0;
 
@@ -38,30 +40,6 @@ export let findProjectRootOfFile = (
   }
 };
 
-// Check if filePartialPath exists at directory and return the joined path,
-// otherwise recursively check parent directories for it.
-export let findFilePathFromProjectRoot = (
-  directory: p.DocumentUri | null, // This must be a directory and not a file!
-  filePartialPath: string
-): null | p.DocumentUri => {
-  if (directory == null) {
-    return null;
-  }
-
-  let filePath: p.DocumentUri = path.join(directory, filePartialPath);
-  if (fs.existsSync(filePath)) {
-    return filePath;
-  }
-
-  let parentDir: p.DocumentUri = path.dirname(directory);
-  if (parentDir === directory) {
-    // reached the top
-    return null;
-  }
-
-  return findFilePathFromProjectRoot(parentDir, filePartialPath);
-};
-
 // Check if binaryName exists inside binaryDirPath and return the joined path.
 export let findBinary = (
   binaryDirPath: p.DocumentUri | null,
@@ -208,35 +186,16 @@ export let getReferencesForPosition = (
     position.character,
   ]);
 
-export let replaceFileExtension = (filePath: string, ext: string): string => {
-  let name = path.basename(filePath, path.extname(filePath));
-  return path.format({ dir: path.dirname(filePath), name, ext });
-};
-
 export const toCamelCase = (text: string): string => {
   return text
     .replace(/(?:^\w|[A-Z]|\b\w)/g, (s: string) => s.toUpperCase())
     .replace(/(\s|-)+/g, "");
 };
 
-const readBsConfig = (projDir: p.DocumentUri) => {
-  try {
-    let bsconfigFile = fs.readFileSync(
-      path.join(projDir, c.bsconfigPartialPath),
-      { encoding: "utf-8" }
-    );
-
-    let result = JSON.parse(bsconfigFile);
-    return result;
-  } catch (e) {
-    return null;
-  }
-};
-
 export const getNamespaceNameFromBsConfig = (
   projDir: p.DocumentUri
 ): execResult => {
-  let bsconfig = readBsConfig(projDir);
+  let bsconfig = lookup.readBsConfig(projDir);
   let result = "";
 
   if (!bsconfig) {
@@ -258,70 +217,38 @@ export const getNamespaceNameFromBsConfig = (
   };
 };
 
-let getCompiledFolderName = (moduleFormat: string): string => {
-  switch (moduleFormat) {
-    case "es6":
-      return "es6";
-    case "es6-global":
-      return "es6_global";
-    case "commonjs":
-    default:
-      return "js";
-  }
-};
-
 export let getCompiledFilePath = (
   filePath: string,
   projDir: string
 ): execResult => {
-  let bsconfig = readBsConfig(projDir);
+  let error: execResult = {
+    kind: "error",
+    error: "Could not read bsconfig",
+  };
+  let partialFilePath = filePath.split(projDir)[1];
+  let compiledPath = lookup.getFilenameFromBsconfig(projDir, partialFilePath);
 
-  if (!bsconfig) {
-    return {
-      kind: "error",
-      error: "Could not read bsconfig",
-    };
+  if (!compiledPath) {
+    return error;
   }
 
-  let pkgSpecs = bsconfig["package-specs"];
-  let pathFragment = "";
-  let moduleFormatObj: any = {};
-
-  let module = c.bsconfigModuleDefault;
-  let suffix = c.bsconfigSuffixDefault;
-
-  if (pkgSpecs) {
-    if (pkgSpecs.module) {
-      moduleFormatObj = pkgSpecs;
-    } else if (typeof pkgSpecs === "string") {
-      module = pkgSpecs;
-    } else if (pkgSpecs[0]) {
-      if (typeof pkgSpecs[0] === "string") {
-        module = pkgSpecs[0];
-      } else {
-        moduleFormatObj = pkgSpecs[0];
-      }
-    }
-  }
+  let result = compiledPath;
 
-  if (moduleFormatObj["module"]) {
-    module = moduleFormatObj["module"];
-  }
+  // If the file is not found, lookup a possible root bsconfig that may contain
+  // info about the possible location of the file.
+  if (!fs.existsSync(result)) {
+    let compiledPath = lookup.getFilenameFromRootBsconfig(
+      projDir,
+      partialFilePath
+    );
 
-  if (!moduleFormatObj["in-source"]) {
-    pathFragment = "lib/" + getCompiledFolderName(module);
-  }
+    if (!compiledPath) {
+      return error;
+    }
 
-  if (moduleFormatObj.suffix) {
-    suffix = moduleFormatObj.suffix;
-  } else if (bsconfig.suffix) {
-    suffix = bsconfig.suffix;
+    result = compiledPath;
   }
 
-  let partialFilePath = filePath.split(projDir)[1];
-  let compiledPartialPath = replaceFileExtension(partialFilePath, suffix);
-  let result = path.join(projDir, pathFragment, compiledPartialPath);
-
   return {
     kind: "success",
     result,