Mattermost Professional?

KINDAYou can build the valuable core, but the established product has meaningful operational complexity. Pick one narrow promise for v1.

BUILD FIRST

One specific customer type and one primary use case
A vertical slice that completes the main job without manual workarounds
Visible limits, review steps, and a fallback when an external dependency fails

LEAVE FOR LATER

Broad third-party integrations
High-scale collaboration, syncing, and permissions
Automation that can cause harm without human review

RESEARCH NOTES

What this tool actually does.

Checked 2026-09-06

Mattermost Professional is a paid, self-hosted plan of Mattermost, a channel-centric collaboration platform aimed at technical and operational teams of up to ~250 users running sovereign ChatOps. Features: public/private channels, 1-1/group messaging, threaded discussions with a thread inbox, file sharing and link/media previews across web, desktop (Windows/macOS/Linux) and mobile (iOS/Android), custom emoji, guest accounts, custom user groups (mention up to 256 users), read-only announcement channels, system-wide notification banners, and granular team permissions. Search covers up to 3 million posts; unlimited search history is listed in official documentation. Calls: 1:1 and group audio with screen sharing up to ~50 concurrent users per self-hosted server. Security/identity: MFA with enforcement, SSO via SAML, OpenID Connect, OAuth 2.0 (Google, GitLab, Entra ID), and AD/LDAP user sync

SOURCES

RESEARCHED BUILD PROMPT

Give this to your coding agent.

Build a self-hosted, channel-based team collaboration server that reproduces the workflow of Mattermost Professional: organizations run their own server to give teams persistent public/private channels, 1-1/group DMs, threaded conversations with an inbox, file sharing with previews, searchable message history, custom emoji, and system-wide announcement banners. Core workflow: admins create teams and channels with granular permissions; users sign in via SSO (SAML/OIDC) or AD/LDAP sync with MFA enforced; guests are invited to limited channel sets; designated channels can be read-only announcement channels; custom user groups enable mentions to up to 256 users; calls support 1:1 and group audio with screen sharing (up to ~50 concurrent per server).

Technical requirements: self-hosted Go or Node.js backend with PostgreSQL, WebSocket-based realtime messaging, S3-compatible file storage, REST API, React web client (responsive; do not replicate Mattermost's UI), WebRTC with an SFU for group calls, Redis for presence, and configurable search depth via Postgres full-text or Elasticsearch depending on post-count target. Use standard middleware for OIDC/SAML. Provide a plugin/webhook system for bots and integrations, plus pre-packaged GitHub, GitLab, and generic webhook connectors. Include an 'interactive AI bot' scaffold that responds in-thread using recent channel context.

Explicitly out-of-scope: horizontal scaling for millions of users, native mobile apps (responsive web only), compliance attestations (FedRAMP/SOC2), and a commercial marketplace.

Deliver a README with setup (docker-compose and bare-metal), config table (DB, SSO, file storage), and important limitations (max group call size, search index cap, no offline message persistence guarantees). Do not use the Mattermost name, logo, or any of its UI layout — create an original visual design.

Do not copy the original brand, proprietary assets, or UI; create an original visual system.

Visit the official product page