When some of your people, customers or partners use Slack, Zoom or Webex and the rest use Microsoft Teams, conversations get split and meetings get awkward. There are two separate problems: chat (messages and DMs) and meetings (joining the other platform's calls). Different tools solve each. This guide covers the options visible today, not every product on the market, and the best pick for each pair.
Chat vs meetings: two different problems
- Chat interop keeps two-way messaging flowing between apps. Built-in apps mostly send notifications or links. Real two-way chat with threads, reactions and files needs a chat federation service.
- Meeting interop lets people or meeting rooms join another platform's meetings. That's covered mostly by native features from Microsoft, Zoom, Cisco and Slack.
Options compared
| Option | Type | Platforms with Teams | Two-way chat | Meetings | White-label for providers |
|---|---|---|---|---|---|
| TeamMate ChatBridge | Chat federation | Slack, Zoom, Webex: chat and DMs; cross-tenant Teams; SIP/XMPP systems | Yes: threads, reactions, edits and deletes; files with the Unified Connector App | No (chat only) | Yes |
| Mio | Chat interop | Google Chat, Slack, Webex, Zoom Team Chat (Zoom ending Oct 31, 2026) | Yes | No | No |
| NextPlane OpenHub | Chat interop | Slack, Webex, Zoom Chat, Google Workspace | Yes | No | No |
| Slack: Microsoft Teams Calls app | Native app | Slack | No | Start or join Teams meetings from Slack | No |
| Teams Rooms third-party join | Native (Microsoft) | Zoom, Webex, others | No | Teams Rooms join Zoom and Webex meetings | No |
| Zoom Interop for Microsoft Teams | Native (Zoom) | Teams | No | Zoom Rooms join Teams meetings | No |
| Cisco Video Integration for Teams (VIMT) | Cloud video interop | Teams | No | Cisco devices join Teams meetings | No |
Sources: Mio app listing, Mio for Zoom, NextPlane OpenHub, Slack help, Microsoft Learn: third-party join, Zoom support, Webex help.
Best picks by pair
Teams and Slack
- Chat: TeamMate ChatBridge. Full two-way messaging, with the sender, threads and formatting preserved. It bridges chat and direct messages, needs nothing installed on user devices, never saves messages, and comes under SOC 2 Type 2. It comes in two versions: Federated Chat stores nothing and doesn't transfer files, and the Unified Connector App adds file sharing, storing only files, in the customer's own SharePoint. See ChatBridge vs Mio.
- Meetings: Slack's Microsoft Teams Calls app lets Slack users start a Teams meeting with
/teams-callsand join from Slack.
Teams and Zoom
- Chat: TeamMate ChatBridge. It connects Zoom chat and direct messages with Teams, keeping threads, reactions and edits, just as it does for Slack and Webex, plus files with the Unified Connector App. One bridge covers every platform your customers use. (Mio announced its Zoom integration ends Oct 31, 2026.)
- Meetings: native room interop. Teams Rooms can join Zoom meetings, and Zoom Rooms can join Teams meetings without extra licensing, using the Teams web client. SIP-based joins need a Microsoft Cloud Video Interop subscription.
Teams and Webex
- Chat: TeamMate ChatBridge. It federates Webex chat and direct messages alongside Teams, Slack and Zoom. More in How to connect Teams with Webex.
- Meetings: Teams Rooms can join Webex meetings with Direct Guest Join or SIP join. Cisco devices can join Teams meetings with Cisco Video Integration for Microsoft Teams.
Teams to Teams: guest access vs federation
Not every split is between platforms. Often it's two companies that both use Teams. - Guest access adds an outside person to your tenant as a guest. It suits deep, project-based work, but the guest has to switch tenants and sits inside your environment. - Teams external access lets users chat 1:1 and in groups with people in other Teams organizations when both sides allow it (Microsoft Learn). - ChatBridge connects Teams tenants from different organizations without Microsoft Entra B2B guest access or shared directories, and manages those connections in the same portal as Slack, Zoom and Webex.
What it looks like day to day
A product team works in Slack and needs daily input from IT, which runs on Teams. Without a bridge, people email, screenshot threads and miss updates. With ChatBridge, the product team messages IT from Slack, IT replies from Teams, and the thread and reactions stay intact on both sides.
For service providers: sell chat federation under your brand
If you're a UCaaS provider or MSP, ChatBridge lets you sell cross-platform chat as your own service. It's white-label, manages multiple customer tenants from a single pane, and is priced per user, per month. Mio and NextPlane don't offer a white-label model. See ChatBridge → or start a free 30-day proof of concept.
Frequently asked questions
What is the best way to connect Microsoft Teams and Slack?
For two-way chat, use a chat federation service such as TeamMate ChatBridge, which relays messages, threads and reactions between the two apps in real time, plus files with its Unified Connector App. For meetings, Slack's Microsoft Teams Calls app lets Slack users start and join Teams meetings from Slack.
Can Microsoft Teams and Zoom users chat with each other?
Yes, with a chat federation service. TeamMate ChatBridge connects Zoom chat and direct messages with Teams, keeping threads, reactions and edits, the same as for Slack and Webex. File sharing comes with the Unified Connector App. For meetings, Teams Rooms can join Zoom meetings and Zoom Rooms can join Teams meetings.
Can Microsoft Teams and Webex users chat with each other?
Yes. TeamMate ChatBridge federates Teams chat and direct messages with Webex. For meetings, Teams Rooms can join Webex meetings, and Cisco devices can join Teams meetings through Cisco Video Integration for Microsoft Teams.
Is chat federation the same as Teams guest access?
No. Guest access adds an outside person to your Teams tenant as a guest, so they switch tenants to work with you. Chat federation lets each person stay in their own app or tenant. ChatBridge also connects Teams tenants from different organizations without Microsoft Entra B2B guest access.
Can a service provider offer Teams chat federation under its own brand?
Yes. TeamMate ChatBridge is white-label, so service providers can deploy it under their own brand and manage multiple customer tenants from one pane. Mio and NextPlane don't offer a white-label model.
