Open source alternatives to Microsoft Teams

What Microsoft Teams does

Microsoft Teams is the chat, meetings and calling hub of Microsoft 365. Each team is built on a Microsoft 365 group, with a SharePoint site and document library for its files, and users sign in with identities in Microsoft Entra ID. Teams has channels and chats, scheduled and ad-hoc meetings, calling, guest and external access, and a platform for third-party apps. Administration happens in the Teams and Microsoft 365 admin centers.

Why people look for an alternative

• Tied to Microsoft 365. Identity, files and administration all live in Microsoft’s ecosystem: Entra ID for accounts, SharePoint and OneDrive for files, Microsoft Graph for automation. Moving away means replacing more than chat.
• Data held by a third party. Teams data is stored in the geographic region of the Microsoft 365 tenant. Local residency in several countries is offered only to new tenants; existing tenants in those countries stay in regional locations such as APAC, the Americas or EMEA.
• Limited end-to-end encryption. Traffic is encrypted with TLS and SRTP by default, but end-to-end encryption is available only for one-to-one calls, where it is off by default, and for meetings scheduled by organizers with a Teams Premium license. Recording, live captions and other service-side features stop working while it is on.
• Exporting messages. Programmatic export of chats and channel messages goes through the Teams Export APIs and requires an active Teams license for each user whose data is exported.
• No self-hosted option. Teams runs only as a Microsoft cloud service.

What to compare in an alternative

1. Scope. Do you need only chat, or chat with calls, meetings and shared files? Some tools cover all three, others focus on messaging and hand calls to Jitsi or similar.
2. Encryption. Whether messages and calls are end-to-end encrypted by default (Element, Wire), optionally (Rocket.Chat), or protected in transit and at rest on your own server.
3. Identity integration. SSO with SAML or OpenID Connect and LDAP or Active Directory sync, and whether they are in the free or paid edition.
4. Federation and external users. Guest access, federation between organizations, and bridges to Teams during a transition.
5. Self-hosting effort. From a Nextcloud app install to a multi-service Kubernetes deployment.
6. Migration. Zulip documents an importer for Microsoft Teams data; check the export options available on your Microsoft 365 plan.

Which one to choose

For chat, calls and files together, Nextcloud Talk is the closest match, since it runs inside a Nextcloud server with file storage and calendars; larger meetings need its High Performance Back-end. For end-to-end encryption by default, Wire offers MLS-based encryption with an EU-hosted cloud or an on-premises deployment, and Element brings encrypted, federated chat and Element Call on the open Matrix standard. If channel-based team chat with built-in calls and many integrations is the priority, Mattermost and Rocket.Chat are the established choices, with SSO and compliance features in their paid editions.