Are Web Add-ins coming to desktop OneNote?

Do not plan on a OneNote Office Web Add-in becoming available in desktop OneNote: build it for OneNote on the web only if that is an acceptable deployment target, or choose a separate desktop integration model for a desktop-first solution.

Current support

Microsoft’s current platform matrix lists only Office on the web for OneNote Office Add-ins, with these capabilities:

• Content add-ins
• Task panes
• Add-in commands
• OneNoteApi 1.1

It does not list OneNote on Windows or Mac as supported Office Add-in hosts.^1^ The OneNote JavaScript API requirement-set page likewise lists OneNoteApi 1.1 as supported only in Office on the web.^2^

There is currently no published Microsoft commitment or timetable for bringing this model to desktop OneNote. The general statement that OneNote supports Office Add-ins means OneNote is an Office Add-ins application; it does not imply that every OneNote client is a supported host. Microsoft’s glossary specifically excludes OneNote from its list of desktop clients supporting Office Add-ins.^3^

Recommended development choices

Choose according to where the functionality must run:

1. OneNote on the web is sufficient:
   Build an Office Web Add-in with HTML, CSS, JavaScript, and OneNoteApi 1.1. Microsoft continues to document development, testing, debugging, and publication for this model.^4^ Use a runtime requirement check before calling the OneNote API:

      Office.onReady(() => {
        const supported =
          Office.context.requirements.isSetSupported("OneNoteApi", "1.1");
   
        if (!supported) {
          showUnsupportedClientMessage();
          return;
        }
   
        startOneNoteAddIn();
      });
   

   This check can provide an alternate message or workflow, but it cannot enable the add-in in desktop OneNote.^2^
2. The solution must run inside desktop OneNote on Windows:
   Investigate the legacy OneNote Win32 desktop interfaces and COM add-in model. The desktop Application interface exposes a COMAddIns collection.^5^ However, Microsoft characterizes these APIs as intended for Win32 desktop solutions in unconnected scenarios, and the associated reference targets the OneNote 2013 desktop API.^6^ This is Windows-specific legacy extensibility, not a portable Office Web Add-in. Treat it as a separate client implementation and validate that the documented API covers the required operations before committing to it.
3. The feature can run as a separate application or service:
   Use Microsoft Graph to work with cloud notebooks, sections, and pages. This can support users across platforms because the integration is not hosted inside a particular OneNote client.^7^ It will not provide a native desktop OneNote task pane or ribbon command.

A practical architecture is to keep business logic and server-side services shared, then provide either:

• a OneNote web add-in as the browser client;
• a separate Windows desktop integration if essential; or
• an external Graph-based application.

Do not make desktop support dependent on an unannounced future release. Monitor the platform-availability matrix for a OneNote Windows or Mac row, and submit the requirement through the feature-request link on the OneNote add-ins documentation page.^4^

References

1. Office client application and platform availability for Office Add-ins ...
2. OneNote JavaScript API requirement sets
3. Office Add-ins glossary
4. OneNote add-ins documentation - Office Add-ins | Microsoft Learn
5. Application interface (OneNote)
6. OneNote developer reference
7. OneNote API overview