Teams App/Extension Not showing in External-user initiated chats.

[glr0221]

Hello MS-Teams-Library team,

We currently released the first version of our app/extension which allows users to conveniently report suspicious (chat/channel) messages to their admins. Our current implementation is using a bot and a client-side extension loaded on an iframe. We have an Outlook version of this app as well.

What I would like to ask assistance for, is how to get our Teams App to work (shown or enabled) whenever a group chat or individual chat is initiated by an external user. I have read and understood your documentation but would still like to confirm if it is possible for our addin to be enabled for external-user-initiated chat(s). What do we need to change in our implementation to be able to support this? Or is there any server-side configuration that we can set to enable this feature?

We would really like our addin to be a part of the addin list like 'Share to Outlook' or even under 'More Actions'.

Looking forward to your positive response.

Thank you very much.

[Prasad-MSFT]

Hi @glr0221 thanks for raising your issue.

Can a Teams App (Bot/Extension) Be Enabled for External-User-Initiated Chats?

Current Microsoft Teams Platform Limitations:

• App Availability in External Chats: As of now, Microsoft Teams does not support enabling or pinning custom apps (including bots, messaging extensions, or client-side extensions) in 1:1 or group chats that are initiated by external users (users outside your organization/tenant).
• Add-in List & “More Actions”: Custom apps can appear in the “More Actions” menu or as message actions, but only in chats where the app is installed and allowed by policy. For external chats, Microsoft restricts the use of most custom apps for security and compliance reasons.
• Outlook vs. Teams: Outlook add-ins can sometimes be enabled for external senders, but Teams has stricter boundaries for external and guest access.

What Can You Do?

• Internal Chats: Your app can be enabled and shown for internal 1:1, group, and channel chats as long as it is installed and allowed by policy.
• External/Guest Chats: There is currently no supported way to automatically enable or show your app in chats initiated by external users. This is a platform limitation for all custom Teams apps.
• Message Actions: Even message actions (like “Report Message”) are not available in external chats for custom apps.

Server-Side or Policy Configuration?

• No Server-Side or Policy Setting currently exists to override this limitation.
• App Permission Policies and Setup Policies only apply to users and chats within your own tenant.

[glr0221]

Thank you for your responses @Prasad-MSFT .

This makes things very clear.
Is there any way hope for custom apps to be enabled for external-user initiated chats?
How do we file a feature request?

Right now, I think 'share with outlook' is available for external and internal chats.
I hope someday, there is a way for us to make our app work like 'share with outlook' button.

Thank you.

[Prasad-MSFT]

At the moment, this is a platform-level limitation in Microsoft Teams, and there hasn’t been any public roadmap commitment confirming support for custom apps (bots, messaging extensions, or message actions) in external-user-initiated chats.

To achieve your requirements, we recommend you give your feedback in Teams Feedback Portal. Feature requests are reviewed by the engineering team and may be prioritized based on various factors, including the number of requests received.