Auto approve a join request

Hi belasor ,

That's an internal API used by the Teams UI, it's not documented and realistically you'll struggle to achieve authentication for any other process to call it. There is an unofficial powershell that tries, but it's majorly unsupported.

The official supported apis for Teams are at graph.microsoft.com. There isn't an api to specifically approve a request, but you can just add a member, this would clear the pending request anyway. See Add member to team - Microsoft Graph beta | Microsoft Docs.

I'm not sure I really see what you are trying to achieve, why not make the group Public then there simply isn't a need for a user to be approved or added, they just join immediately.