Debug your event-based or spam-reporting Outlook add-in

This article discusses the key debugging stages to enable and set breakpoints in your code as you implement event-based activation or integrated spam reporting in your add-in. Before you proceed, we recommend reviewing the troubleshooting guide for additional steps on how to resolve development errors.

To begin debugging, select the tab for your applicable client.

Web

Use your preferred browser's developer tools to debug your event-based add-in in Outlook on the web. For more information, see Debug add-ins in Office on the web.

Windows (new)

To debug your add-in in new Outlook on Windows desktop client (preview), you must run the following command to open Microsoft Edge DevTools.

olk.exe --devtools

For more information, see the "Debug your add-in" section of Develop Outlook add-ins for the new Outlook on Windows.

Windows (classic)

If you used the Yeoman generator for Office Add-ins to create your add-in project (for example, by completing an event-based activation walkthrough), follow the Created with Yeoman generator option throughout this article. Otherwise, follow the Other steps. Visual Studio Code should be at least version 1.56.1.

Mark your add-in for debugging and set the debugger port

1. Get your add-in's ID from the manifest.

   • Add-in only manifest: Use the value of the <Id> element child of the root <OfficeApp> element.
   • Unified manifest for Microsoft 365: Use the value of the "id" property of the root anonymous { ... } object.

2. Create a registry DWORD value named UseDirectDebugger in HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Wef\Developer\[Add-in ID]. Replace [Add-in ID] with your add-in's ID from the manifest.

   Note

   If the Developer key (folder) doesn't already exist under HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\WEF\, complete the following steps to create it.

   1. Right-click (or select and hold) the WEF key (folder) and select New > Key.
   2. Name the new key Developer.

   Created with Yeoman generator: In a command line window, navigate to the root of your add-in folder then run the following command.

   npm start
   

   In addition to building the code and starting the local server, this command sets the UseDirectDebugger registry DWORD value data for this add-in to 1.

   Other: In the HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\WEF\Developer\[Add-in ID]\UseDirectDebugger registry DWORD value, where [Add-in ID] is your add-in's ID from the manifest, set the value data to 1.

3. In the registry key HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Wef\Developer\[Add-in ID], where [Add-in ID] is your add-in's ID from the manifest, create a new DWORD value with the following configuration.

   • Value name: DebuggerPort
   • Value data (hexadecimal): 00002407

   This sets the debugger port to 9223.

4. Start Outlook or restart it if it's already open.

5. Perform the action to initiate the event you're developing for, such as creating a new message to initiate the OnNewMessageCompose event or reporting spam messages. The Debug Event-based handler dialog should appear. Do not interact with the dialog yet.

   

Configure Visual Studio Code

Created with Yeoman generator

1. Back in the command line window, run the following to open your add-in project in Visual Studio Code.

   code .
   

2. In Visual Studio Code, open the ./.vscode/launch.json file and add the following excerpt to your list of configurations. Save your changes.

   {
     "name": "Direct Debugging",
     "type": "node",
     "request": "attach",
     "port": 9223,
     "timeout": 600000,
     "trace": true
   }
   

Other

1. Create a new folder called Debugging (perhaps in your Desktop folder).

2. Open Visual Studio Code.

3. Go to File > Open Folder, navigate to the folder you just created, then choose Select Folder.

4. On the Activity Bar, select Run and Debug (Ctrl+Shift+D).

   

5. Select the create a launch.json file link.

   

6. In the Select Environment dropdown, select Edge: Launch to create a launch.json file.

7. Add the following excerpt to your list of configurations. Save your changes.

   {
     "name": "Direct Debugging",
     "type": "node",
     "request": "attach",
     "port": 9223,
     "timeout": 600000,
     "trace": true
   }
   

Attach the debugger

The bundle.js file of an add-in contains the JavaScript code of your add-in. It's created when classic Outlook on Windows is opened. When Outlook starts, the bundle.js file of each installed add-in is cached in the Wef folder of your machine.

1. To find the add-in's bundle.js file, navigate to the following folder in File Explorer. Replace text enclosed in [] with your applicable Outlook and add-in information.

   %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\{[Outlook profile GUID]}\[Outlook mail account encoding]\Javascript\[Add-in ID]_[Add-in Version]_[locale]
   

   Tip

   If the bundle.js file doesn't appear in the Wef folder, try the following:

   • If your add-in is installed or sideloaded, restart Outlook.
   • Remove your add-in from Outlook, then sideload it again.

2. Open bundle.js in Visual Studio Code.

3. Place breakpoints in bundle.js where you want the debugger to stop.

4. In the DEBUG dropdown, select Direct Debugging, then select the Start Debugging icon.

   

Run the debugger

1. After confirming that the debugger is attached, return to Outlook, and in the Debug Event-based handler dialog, choose OK .

2. You can now hit your breakpoints in Visual Studio Code, enabling you to debug your event-based activation or spam-reporting code.

Stop the debugger

To stop debugging the rest of the current Outlook on Windows session, in the Debug Event-based handler dialog, choose Cancel. To re-enable debugging, restart Outlook.

To prevent the Debug Event-based handler dialog from popping up and stop debugging for subsequent Outlook sessions, delete the associated registry key, HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Wef\Developer\[Add-in ID]\UseDirectDebugger, or set its value to 0.

Stop the local server

When you want to stop the local web server and uninstall the add-in, follow the applicable instructions:

• To stop the server, run the following command. If you used npm start, the following command should also uninstall the add-in.

  npm stop
  

• If you manually sideloaded the add-in, see Remove a sideloaded add-in.

Mac

Event-based add-ins that run in Outlook on Mac use the browser runtime. Because of this, you can debug your add-in using Safari Web Inspector.

1. To use the Safari Web Inspector in Outlook, follow the steps in Debugging with Safari Web Inspector on a Mac.
2. Open Outlook, then sideload your add-in.
3. Perform an action that will initiate the event your add-in handles. For example, create a new message to initiate the OnNewMessageCompose event. This opens an empty Developer Window. The name of your add-in appears in the title bar of the window.
4. Right-click (or select and hold) anywhere in the Developer Window, then select Inspect Element. This opens the Inspector, where you can set breakpoints and debug your add-in.

See also

• Configure your Outlook add-in for event-based activation
• Implement an integrated spam-reporting add-in
• Troubleshoot event-based and spam-reporting add-ins
• Debug your add-in with runtime logging