Reactions in external setups
When using Conclude to bridge Slack and Microsoft Teams for external, cross-company collaboration, reactions, – emoji responses to messages – work differently depending on whether the user who reacted has an account on both platforms. This page explains the expected behavior and current limitations.
Reactions work without limitations
Reactions sync seamlessly in both directions when the user who reacted is signed in and has a recognized account on both the Slack and Teams sides of the connection.
✅ Full sync — no action needed |
The reaction and the identity of the person who reacted are correctly displayed on the receiving platform. No integration account is involved, and there are no display restrictions. |
External setup: users are not on both platforms
In a typical setup, users from one company are on Slack and users from another are on Teams (or vice versa). Most users only exist on one platform. In these cases, Conclude falls back to using the integration account to post reactions on behalf of the user.
Teams → Slack (reactions from Teams to Slack)
Reactions this way work with some limitations:
- The reaction is posted in Slack by the Conclude Bot (integration account), and not by the individual Teams user
- Because the bot posts the reaction, Slack users cannot see who on the Teams side originally reacted
- There is a limit to how many reactions the bot can post
Slack → Teams (reactions from Slack to Teams)
Reactions in this direction have stricter limitations due to a Microsoft API restriction:
⚠️ Microsoft API limitation |
Microsoft has not yet updated its Teams API to allow setting multiple emoji reactions for a single user. As a result, Conclude can sync only the most recent reaction from Slack to Teams using the integration account. Earlier reactions are not reflected. |
For this sync to work, an integration user account must be set up on the Teams side by an admin and be properly authenticated. If no matching user is found and no integration account is configured, reactions from Slack will not appear in Teams.
Requirements for reaction syncing in external setups
To enable the best possible reaction syncing in a cross-company collaboration setup:
- An integration account must be configured on the Teams side
- The integration account must be Teams-licensed and successfully authenticated
- The connection must be established from one side, with the other side having accepted the invite
- Both platforms must be actively connected, and the bridge must be running
Scenarios: what to expect
Scenario | Result | Notes |
User exists on both platforms | ✅ Full sync | Reactions appear with the correct identity on both sides |
Teams user reacts → Slack | ⚠️ Partial sync | Reaction posted by Conclude Bot; identity not shown; count may be limited |
Slack user reacts → Teams (integration account configured) | ⚠️ Partial sync | Only the latest reaction is synced; multiple reactions not supported by the Teams API |
Slack user reacts → Teams (no integration account) | ❌ Not synced | No matching user found; reaction is dropped |
Frequently asked questions
Why can I only see one reaction in Teams?
This is a current limitation of the Microsoft Teams API. Until Microsoft supports multiple emoji reactions per user in their API, only one reaction (the most recent) can be synced from Slack to Teams via the integration account.
Can I see who on the other platform reacted?
Only if that user has accounts on both platforms and is signed in. When the integration account posts a reaction on behalf of an external user, the originating identity is not shown.
Will this improve in the future?
Yes. Conclude will update reaction sync behavior as Microsoft expands their Teams API capabilities. No action is required on your end when that happens.