A Slack channel on your side, a Microsoft Teams channel on theirs, messaging both ways in real time - including when the two channels belong to different companies.
Quick answer. There is no native Slack to Microsoft Teams integration, so connecting the two takes a bridge. With SlackBridge you sign in to Slack, invite the other organization, and map one Slack channel to one Microsoft Teams channel. Their Microsoft 365 administrator approves the connection once. After that, messages, threaded replies, reactions, @mentions and - where it is switched on - files move between the two channels in real time, while each side stays on the platform it already uses.
Your own setup takes about two minutes. When the Teams channel belongs to another company, the thing that actually gates go-live is their administrator granting consent, so plan for their IT schedule rather than yours.
Your team uses Slack. Your clients, partners, or other departments use Microsoft Teams. Neither side wants to switch. Communication falls back to slow email threads and forwarded screenshots.
Microsoft deprecated their Slack connector for Teams in 2024. There is no built-in way to connect Slack channels to Teams channels. Power Automate introduces delays. Zapier polls instead of streaming.
Most integration tools assume you control both platforms. In reality, your Slack workspace and your client's Teams tenant are in different organizations with separate IT departments and security policies.
SlackBridge connects to Slack via OAuth and to Microsoft Teams via the Microsoft Graph API. When someone sends a message in a mapped Slack channel, SlackBridge receives it instantly via webhook, then posts it to the corresponding Teams channel. Replies from Teams flow back to Slack the same way. Messages appear in seconds, not minutes.
Each side sees messages from the other platform as bot posts with the sender's name. Users stay on their preferred tool and communicate as if everyone were in the same channel.
Sign in with Slack OAuth. 30 seconds, no IT approval needed.
Send an invite link. Your contact or their IT admin authorizes the Teams connection.
Pick which Slack channel connects to which Teams channel.
Real-time two-way messaging. Both sides stay on their tool.
Most integration tools quietly assume one IT department owns both platforms. Cross-organization bridging is a different problem: your Slack workspace and the other company's Microsoft 365 tenant have separate administrators, separate security policies, and separate approval processes. Here is what that actually involves.
Their administrator picks one of two permission sets at consent time. Core Bridging is six read-leaning Microsoft Graph permissions, for tenants with strict policies. Full Integration is eleven, adding team and app management so SlackBridge can install its own bot and create channels rather than asking an admin to do it by hand. SlackBridge never asks for Mail, Calendar, chat-send, Files or OneDrive permissions. The one SharePoint permission it holds, on Full Integration only, is Sites.Selected, which grants nothing until an administrator names a specific site for private or shared channel files. Their administrator can review the grant, narrow it, or remove it entirely from Microsoft Entra at any time.
Messages, threaded replies, reactions and @mentions cross in both directions between the two mapped channels. Files cross on connections where file sharing is switched on. Nothing else does: SlackBridge reads no other channel, no mailbox, no calendar and no document library, and the text of a bridged message is never stored on SlackBridge servers.
A single Slack workspace can hold connections to several Microsoft Teams tenants at once, each with its own mappings and its own consent, which is how an agency or MSP runs a channel per client without a separate tool per customer. Each client organization's administrator only ever sees and approves their own tenant's connection.
| Feature | SlackBridge | Power Automate | Slack Connect | Zapier |
|---|---|---|---|---|
| Slack to Teams messaging | Yes | Delayed | No (Slack only) | Delayed |
| Real-time delivery | Seconds | Polling; Microsoft documents a 3-minute interval for the Teams trigger, varying by trigger and plan | Seconds | 5-15 min |
| Two-way messaging | Yes | Complex setup | Yes | Complex setup |
| Cross-org support | Yes | Same tenant | Both need Slack | Same tenant |
| No-code setup | 2 minutes | Build flows | Simple | Build zaps |
| Multi-tenant | Multiple client tenants; capacity set by your plan and add-ons | No | No | No |
| Free tier | 1 connection | Limited | Paid plan | Limited |
Your creative or marketing agency stays on Slack. Your Fortune 500 clients stay on Teams. Project updates, feedback, and approvals flow between both in real-time.
Connect your single Slack workspace to each client's Teams tenant. One inbox, many client relationships, zero context switching.
MSPs supporting multiple organizations. Bridge support channels into each customer's Teams environment without managing multiple chat apps.
Migrating from Slack to Teams? Bridge channels during the transition so departments can communicate regardless of which tool they are on.
Yes. That is the case SlackBridge is built for. Your organization keeps Slack, the other organization keeps Microsoft Teams, and one Slack channel is mapped to one Teams channel in their tenant. Messages relay both ways in real time. Neither side migrates, and nobody has to join the other company's platform.
No. Only the Slack-side organization has an account and a plan. The Microsoft Teams organization grants a one-time admin consent and then uses SlackBridge as a regular Teams app. It buys nothing and is not metered.
No. Nobody on the Teams side needs a Slack account, a Slack licence, or a guest seat. They read and reply in their own Teams channel.
One of two Microsoft Graph permission sets, chosen at consent time. Core Bridging is six read-leaning permissions. Full Integration is eleven, adding team and app management so SlackBridge can install its own bot and create channels for you. SlackBridge never requests Mail, Calendar, chat-send, Files or OneDrive permissions on Microsoft 365. The one SharePoint permission it holds, on Full Integration only, is Sites.Selected, which grants nothing until an administrator names a specific site for private or shared channel files. The administrator can review or revoke the grant later from Microsoft Entra.
Yes. Each tenant is a separate connection with its own channel mappings, which is how agencies, consultancies and MSPs run many clients from one workspace. How many you can run at once is a plan limit: the free plan covers one external organization and one linked channel, Pro covers two organizations and five channels, and further capacity is added one unit at a time.
On the Slack side, yes: invite the SlackBridge bot to the private channel and it becomes available to map. SlackBridge can only see private channels it has been invited to. On the Microsoft side, a private or shared Teams channel relays messages normally, but @mentions are switched off in both directions there, because confirming who belongs to such a channel needs a Graph permission SlackBridge does not request. Bridge a standard Teams channel if mentions matter to your team.
Yes. A reply in a thread arrives as a reply in the corresponding thread on the other platform rather than as a loose message in the channel. SlackBridge resolves the parent from a stored message ID.
Yes, since September 2026. SlackBridge posts the list of addressable names into each bridged channel; type one exactly as shown and that person gets a real notification on the other platform. Microsoft Teams will not suggest these names as you type, so type the name as plain text rather than picking from the Teams popup. Mentions do not work in private or shared Teams channels, and not in a message whose file SlackBridge copies across.
Yes, on connections that have file sharing on: the file itself is copied into the mapped channel in both directions, and images pasted straight into a Teams message arrive in Slack as real images. New Full Integration installs have this on from the start, covered by the administrator's consent at install, and any admin can switch it off per connection. Core Bridging connections, and connections created before September 2026 that never enabled it, announce a file by name and type instead. Files pass through in transit and are never stored on SlackBridge servers.
Not on SlackBridge. The body text of a bridged message is never persisted. Each relayed message leaves a small metadata record (Slack timestamp, Teams message ID, channel IDs) in encrypted key-value storage for seven days so threading works, and that record deliberately excludes sender names and message text. Seven days is fixed on every plan. The conversation itself lives in Slack and in Teams, in each platform's own history and audit trail.
Revoking consent is not a single switch, and it is worth knowing which half it stops. Deleting the SlackBridge enterprise application in Microsoft Entra removes SlackBridge's Graph access to that tenant, which stops Teams to Slack relaying. Messages going the other way, Slack to Microsoft Teams, are delivered by the SlackBridge bot rather than by a tenant token, so they continue until the SlackBridge app is also removed from the team. To stop both directions at once, do both, or ask SlackBridge support to disable the channel mapping, which takes effect immediately.
Slack Connect joins a Slack workspace to another Slack workspace. It cannot put a message into a Microsoft Teams channel, so it does not help when the other organization is on Microsoft 365 and will not adopt Slack. SlackBridge is the cross-platform case: Slack on one side, Microsoft Teams on the other.
About two minutes to set up your side. The free plan includes 1 external organization and 1 linked channel, and needs no credit card.
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