Limitations

OpenTeams is an early implementation. This page lists what it does not do, so you can decide before you rely on it.

Not Microsoft Teams

OpenTeams is not Microsoft Teams, is not affiliated with Microsoft and makes no claim of feature parity. It implements:

• channels, posts with replies, reactions, author-only edit and delete, search and unread counts;
• presence: who is online, typing, and an availability you set (available, busy, away);
• meetings in a channel: audio, video, screen share and raise hand, with a pre-join screen;
• files shared in the conversation as links, with Word, Excel, PowerPoint and Visio files recognised by name.

It does not implement 1:1 or group chats outside channels, threads as separate panes, notifications, a calendar, recording, background blur or live captions.

Content workspace

Word previews read-only; Excel offers local editing and saving new channel copies when storage is configured; Visio uses its existing viewer. There is no coediting, overwrite or versioned save-back. PowerPoint needs a host-configured embedded viewer page. Missing integrations are reported in the pane. Text reads are limited to 2 MiB and native Office reads to 32 MiB.

Files views support direct upload, blank Excel creation and metadata search when storage is configured. Uploads show a busy state and allow retry, with no byte progress or cancellation. Failed batches can leave unreferenced storage objects; the reference server has no cleanup contract for these objects. Folders, document content indexing, file version history and authenticated file permissions are not implemented.

Markdown supports headings, bullets, quotes, fenced code, basic emphasis and web links. It does not yet implement full CommonMark/GFM, tables, task lists, nested structures or relative links. Raw HTML is displayed as text.

Websites and HTML attachments use a sandbox without same-origin, popup or top navigation permission. Some sites block embedding or require permissions this sandbox does not grant. External open remains available. File and website tab definitions can be shared in channels; the embedded app platform, authentication and permissions of Microsoft Teams are not implemented. Tab creator checks run in the client and require server authorization to become enforceable.

Security and privacy

• No end-to-end encryption. Chat travels as Yjs updates through your server, which can read and stores them. Uploaded files are stored as they are. Call media is DTLS-SRTP between peers (a TURN relay cannot decrypt it).
• Authorization is the server's job. Author and role checks run in the client; a hostile client can write anything the server accepts.
• The reference server has no user accounts. Its token is one shared secret stored in the browser, not per-user authentication. See what the reference server does not do.
• Presence is advisory and unauthenticated, like any Yjs awareness: a client can claim any name.
• Everything a peer sends is re-validated when read back and rendered as text, never as markup.

Scale

• Mesh calls connect every participant to every other one. That needs no media server and works for a handful of people (the default cap is 12), not a webinar.
• History grows. The reference server keeps one snapshot per room and never compacts it.
• One server process. The reference server keeps rooms in memory and does not scale horizontally.

Local mode and the live demos

mode: 'local' uses BroadcastChannel, so only tabs of the same browser on the same site see each other. Nothing is sent to any server, files are shared by name only (there is nowhere to upload them), and the shared document is kept in that browser's localStorage. The live demos run this way because GitHub Pages cannot host a server.

Calls across networks

Public STUN works on open networks. Behind symmetric NAT or strict firewalls you need your own TURN server; without it, some calls will not connect. Cameras and microphones need localhost or HTTPS.