SharePoint Add-ins and Azure ACS
Status: Retired 2 April 2026
The SharePoint Add-in model was a way to extend SharePoint with components that often ran outside it, and Azure Access Control Services (ACS) was the authentication layer many of them used. In SharePoint Online, both were retired on 2 April 2026. This is not a deprecation with room to spare: as of that date, ACS-based authentication stops working.
What they were used for
- SharePoint-hosted add-ins that added UI to a site;
- provider-hosted add-ins running on external servers;
- app-only authentication for unattended scripts and integrations.
What replaces them
| The technology | Move to |
|---|---|
| SharePoint-hosted add-in | SPFx web part or extension |
| Provider-hosted add-in | An external app (for example on Azure), authenticated with Entra ID, and SPFx for anything inside the SharePoint UI |
| Azure ACS authentication | Microsoft Entra ID |
The recommended replacement for the Add-in model is the SharePoint Framework (SPFx), and the replacement for ACS is Microsoft Entra ID. App catalogs are not affected: they continue to host SPFx solutions.
Where this fits
The full picture of what ended and what to build on is in our guide to the state of SharePoint in 2026.