diff --git a/CHANGELOG.md b/CHANGELOG.md
index 295e739b..fc616368 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@
 - Add [`LTeX: Reset and Restart`](https://valentjn.github.io/vscode-ltex/docs/commands.html#ltex-reset-and-restart) command to reset the extension and restart LT<sub>E</sub>X LS (equivalent to reloading the VS Code window)
 - Fix inconsistent titles of German commands
 - Hide internal commands in table of keyboard shortcuts to prevent confusion (see [#282](https://github.com/valentjn/vscode-ltex/issues/282))
+- Engineering: A running instance of LT<sub>E</sub>X LS, if it has been started with `--server-type=tcpSocket`, will be chosen over starting a new instance; this enables simultaneous debugging of vscode-ltex and ltex-ls
 - Update LT<sub>E</sub>X LS to 12.0.0
 
 ## 10.0.0 — “The Unicode Simulation” (April 5, 2021)
diff --git a/src/DependencyManager.ts b/src/DependencyManager.ts
index db80c264..2eecdba7 100644
--- a/src/DependencyManager.ts
+++ b/src/DependencyManager.ts
@@ -13,6 +13,7 @@ import extractZip from 'extract-zip';
 import * as Fs from 'fs';
 import * as Http from 'http';
 import * as Https from 'https';
+import * as Net from 'net';
 import * as Os from 'os';
 import * as Path from 'path';
 import * as SemVer from 'semver';
@@ -612,6 +613,38 @@ export default class DependencyManager {
     return {command: ltexLsScriptPath, args: [], options: {'env': env}};
   }
 
+  public static getDebugServerOptions(): CodeLanguageClient.ServerOptions | null {
+    const executableOptions: ChildProcess.SpawnSyncOptionsWithStringEncoding = {
+          encoding: 'utf-8',
+          timeout: 10000,
+        };
+    const childProcess: ChildProcess.SpawnSyncReturns<string> = ((process.platform == 'win32')
+        ? ChildProcess.spawnSync('wmic', ['process', 'list', 'FULL'], executableOptions)
+        : ChildProcess.spawnSync('ps', ['-A', '-o', 'args'], executableOptions));
+    if (childProcess.status != 0) return null;
+    const output: string = childProcess.stdout;
+
+    const matchPos: number = output.search(
+        /LtexLanguageServerLauncher.*--server-type(?: +|=)tcpSocket/);
+    if (matchPos == -1) return null;
+    const startPos: number = output.lastIndexOf('\n', matchPos);
+    const endPos: number = output.indexOf('\n', matchPos);
+    const line: string = output.substring(((startPos != -1) ? startPos : 0),
+        ((endPos != -1) ? endPos : output.length));
+
+    const match: RegExpMatchArray | null = line.match(/--port(?: +|=)([0-9]+)/);
+    if (match == null) return null;
+    const port: number = parseInt(match[1]);
+    if (port == 0) return null;
+
+    const socket: Net.Socket = new Net.Socket();
+    socket.connect(port, 'localhost');
+
+    return () => {
+      return Promise.resolve({writer: socket, reader: socket});
+    };
+  }
+
   public get vscodeLtexVersion(): string {
     return this._vscodeLtexVersion;
   }
diff --git a/src/extension.ts b/src/extension.ts
index 65b4be23..b9a2a01d 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -66,18 +66,24 @@ async function languageClientIsReady(languageClient: CodeLanguageClient.Language
 async function startLanguageClient(context: Code.ExtensionContext,
       externalFileManager: ExternalFileManager, statusPrinter: StatusPrinter):
       Promise<CodeLanguageClient.LanguageClient | null> {
-  if (dependencyManager == null) {
-    Logger.error('DependencyManager not initialized!');
-    return Promise.resolve(null);
+  let serverOptions: CodeLanguageClient.ServerOptions | null = null;
+
+  if (context.extensionMode == Code.ExtensionMode.Development) {
+    serverOptions = DependencyManager.getDebugServerOptions();
   }
 
-  const success: boolean = await dependencyManager.install();
-  if (success !== true) return Promise.resolve(null);
+  if (serverOptions == null) {
+    if (dependencyManager == null) {
+      Logger.error('DependencyManager not initialized!');
+      return Promise.resolve(null);
+    }
 
-  const statusBarItemManager: StatusBarItemManager = new StatusBarItemManager(context);
+    const success: boolean = await dependencyManager.install();
+    if (success !== true) return Promise.resolve(null);
+    serverOptions = await dependencyManager.getLtexLsExecutable();
+  }
 
-  const serverOptions: CodeLanguageClient.ServerOptions =
-      await dependencyManager.getLtexLsExecutable();
+  const statusBarItemManager: StatusBarItemManager = new StatusBarItemManager(context);
 
   const workspaceConfig: Code.WorkspaceConfiguration = Code.workspace.getConfiguration('ltex');
   const enabled: any = workspaceConfig.get('enabled');
@@ -123,9 +129,11 @@ async function startLanguageClient(context: Code.ExtensionContext,
       null, languageClient, externalFileManager, statusBarItemManager));
   statusPrinter.languageClient = languageClient;
 
-  Logger.log(i18n('startingLtexLs'));
-  Logger.logExecutable(serverOptions);
-  Logger.log('');
+  if ('command' in serverOptions) {
+    Logger.log(i18n('startingLtexLs'));
+    Logger.logExecutable(serverOptions);
+    Logger.log('');
+  }
 
   languageClient.info(i18n('startingLtexLs'));
   const languageClientDisposable: Code.Disposable = languageClient.start();