Community · checked 2026-10-19Can I vibecode Mattermost Professional?
KINDA· weekend project
A chat server for a dozen people is a weekend of code: channels, direct messages, threads, file uploads, search and a WebSocket layer, and an agent can write it on SQLite in a single binary. But Mattermost's own free Team Edition and Entry mode already give a small team that, so building your own only makes sense if you want something much smaller. The paid part is what a one-prompt build doesn't reproduce: SSO through SAML, OpenID Connect or LDAP, advanced permissions, native phone apps with push, a support contract, and a vendor patching security holes. Phone notifications are the biggest gap.
$10/moprice per seat
$120you'd save a year
weekendbuild time
—people replaced it
What you need on hand.
DifficultyIntermediate · Some system setup or keys.
TimeA weekend for a working chat; HTTPS and push notifications take longer
- Claude Code, Codex or CursorAny of them can run the prompt.
- Go 1.23The modernc.org/sqlite driver needs no C compiler.
- A small VPS with a domainPeople need a public HTTPS address, and Web Push won't work without it.
- SMTP credentialsA transactional provider's free tier covers invitations for a team this size.
- An OpenID Connect providerOptional; skip it and use password sign-in.
Before you buildMattermost Team Edition and the free Entry mode run the real product for nothing. Unless you need something smaller, install one of those before building.
- 1. Install one agent: Claude Code, Codex, Cursor.
- 2. Make an empty folder and open it in the agent.
- 3. Paste the prompt below, press enter, and answer its questions as it builds.
The prompt
Build me a small self-hosted team chat to replace Mattermost Professional for up to 15 people. Requirements:
- Go 1.23: one binary using net/http, `github.com/coder/websocket` and `modernc.org/sqlite`
(no CGO), with the web UI embedded through `embed`. `./chat` serves http://localhost:8065;
PUBLIC_URL, SESSION_SECRET and SMTP_* go in .env.
- Storage: ./data/chat.db with users, channels (public, private, direct), memberships, messages
with a thread_id, reactions, read markers and an FTS5 table over message text. Uploads go to
./data/files/ with a 25 MB cap per file.
- Chat: channels, direct messages, threaded replies, @mentions, emoji reactions, editing and
deleting your own messages, unread badges, and live updates over one WebSocket per tab that
reconnects and catches up from the last seen message ID.
- Search: a box backed by FTS5 with filters such as `from:ann in:ops after:2026-01-01`.
- Sign-in: email invitations with a one-time link, Argon2id passwords (`golang.org/x/crypto/argon2`),
and optional OpenID Connect (`coreos/go-oidc`) when OIDC_ISSUER is set. The first user is the
admin and can deactivate users and archive channels.
- ChatOps: one incoming webhook per channel (POST /hooks/<token> with JSON {"text": "..."}) and
a /poll slash command; the README shows how to post from a CI job with curl.
- Notifications: browser Web Push (`github.com/SherClockHolmes/webpush-go`) for mentions and DMs.
- `./chat backup out.db` writes a consistent SQLite backup. No telemetry, local-first; outbound
calls go only to SMTP, your OIDC provider and push services.
- Out of scope: phone apps, voice and video calls, LDAP and SAML, compliance exports, boards, playbooks.
- README: running behind Caddy or nginx with HTTPS, and a warning that Web Push needs HTTPS and
reaches iPhones only after the site is added to the home screen.Opens your agent with the prompt filled in, you press enter. Or copy it and paste it into an empty folder.
Then keep going
Next prompts, same folder.
The first prompt builds the core. Run these one at a time in the same folder to grow it into your own Mattermost Professional.
Extend the team chat in this folder. Requirements: - A per-channel retention setting (keep forever, 90 days, 1 year) enforced by a nightly job that deletes expired messages and their uploads. - An admin-only `./chat export --channel ops out.jsonl` command that writes one JSON object per message with author, timestamp, thread_id, reactions and file names. - Log every purge to ./data/purge.log. - Update the README.
Extend the incoming webhooks of the team chat in this folder. Requirements: - Recognize GitHub push, pull_request and workflow_run payloads (verify X-Hub-Signature-256 with a secret per webhook) and render each as one compact message with links. - Fall back to the plain {"text": "..."} format for everything else. - Show the last 20 deliveries and their status in the admin page. - Update the README with a GitHub setup walkthrough.Add announcement channels to the team chat in this folder. Requirements: - A channel flag `read_only`: only admins and listed posters can post, everyone else can read and react. - Show a banner at the top of the app with the latest announcement until each person dismisses it. - Enforce the rule on the server, including for webhooks and the WebSocket path. - Add tests for every posting path. - Update the README.
Add a /handoff slash command to the team chat in this folder. Requirements: - `/handoff` opens a small form with three fields (open incidents, watch items, notes) and posts the result as a formatted message in the current channel. - Pin the latest handoff in each channel and show it at the top. - Keep handoffs searchable through the existing FTS5 index. - Update the README.
What you lose
- Native iOS and Android apps with a push proxy, and desktop apps
- SAML, OpenID Connect and LDAP single sign-on with user sync
- Advanced team permissions, guest access and read-only announcement channels
- Boards, playbooks and the Jira, GitHub, GitLab and Teams integrations
- Vendor security patches and next-business-day support
Why people still pay
Teams that must keep chat on their own servers pay for the parts around the chat window: sign-in through the company directory, permissions that match the org chart, phone apps that just work, and a vendor to call when an upgrade breaks. Once ten or more people depend on it, running a home-built chat server becomes someone's job.
Mattermost Professional or your own copy?
Seats
Over
Your usage
12h ×$/h
Mattermost Professional, 1 yr$120
Your own copy, 1 yr$115running + build session
You keep$6pays for itself in 9 months
Estimate · A $5 to $12 VPS plus free-tier SMTP. The build is token usage on your agent plan. For comparison, 11 Professional seats at the third-party $10 figure come to $110 a month.
Take your data, then cancel.
1 · Take your data out of Mattermost Professional
- 1Mattermost exports run on the server with mmctl: `mmctl export create --attachments` starts the job and `mmctl export job show` reports its status.
- 2When the job succeeds, `mmctl export list` shows the file name and `mmctl export download` fetches the archive to your machine.
- 3The bulk export is a JSONL file covering teams, channels (public, private and direct), messages and replies, reactions, users, preferences, memberships, custom emoji and bot users.
- 4The docs list webhooks, some configuration and deleted objects as not exported, so write down your integrations and slash commands by hand.
2 · Cancel Mattermost Professional
- 1There is no cancel button: Professional is a prepaid annual license that ends on its expiry date, and admins see a banner 60 days before.
- 2If you don't renew, the server drops to Mattermost Entry on its own: paid features stop working but people can still sign in and chat.
- 3To step down earlier, an admin removes the license key under System Console > About > Edition and License; the docs say you can downgrade without losing data.
- 4For a change or a non-renewal notice, contact a Mattermost Expert or orders@mattermost.com; the docs don't spell out a self-serve flow.
- Entry shows only the latest 10,000 channel messages across all channels. Older ones stay in the database but vanish from view and search, so check your message count first.
- SAML, OpenID Connect and LDAP sign-in and advanced permissions are Professional features; decide how people will sign in after the downgrade.
- Mattermost doesn't give downward adjustments during a term, so reduce seats at renewal rather than mid-year.
- Team Edition is the MIT-licensed free build for small teams that don't need SSO; moving to it keeps the same server and data.
Checked 2026-10-19 against Mattermost Professional's docs: 1, 2, 3, 4, 5, 6
The escape hatch
Don't feel like building it? These are already free.
Mattermost Team EditionOpen sourceThe same server under an MIT license for compiled builds: a single binary plus PostgreSQL, meant for small teams that don't need SSO.★ 39k · active Oct 2026 · docker to self-host
Web, iOS, Android, macOS, Windows, LinuxVisit ↗ZulipOpen sourceApache-licensed team chat that organizes every conversation into topics inside channels; self-host or use the hosted service.★ 26k · active Oct 2026 · docker to self-host
Web, iOS, Android, macOS, Windows, LinuxVisit ↗Rocket.ChatOpen sourceTeam chat under an MIT license, apart from a proprietary ee folder; adds omnichannel and federation options.★ 46k · active Oct 2026 · docker to self-host
Web, iOS, Android, macOS, Windows, LinuxVisit ↗
Web, iOS, Android, macOS, Windows, LinuxVisit ↗ZulipOpen sourceApache-licensed team chat that organizes every conversation into topics inside channels; self-host or use the hosted service.★ 26k · active Oct 2026 · docker to self-host
Web, iOS, Android, macOS, Windows, LinuxVisit ↗Rocket.ChatOpen sourceTeam chat under an MIT license, apart from a proprietary ee folder; adds omnichannel and federation options.★ 46k · active Oct 2026 · docker to self-host
Web, iOS, Android, macOS, Windows, LinuxVisit ↗
The numbers
Mattermost Professional pricing
| Plan | Monthly | Annual, per month | What you get |
|---|---|---|---|
| Entry | $0 | $0 | Self-hosted, all Enterprise Advanced features within caps: 10,000 messages of history across all channels, 1,000 board cards, 5 playbook runs a month, 250 agent queries a month, 40-minute calls. Community support only. |
| Professional | — | $10 | Unlimited search history, LDAP, SAML, OpenID Connect and Entra ID sign-in, MFA enforcement, guest access, advanced team permissions, read-only announcement channels, Teams and Jira integrations, bring-your-own-LLM bot, next-business-day ticket support. |
| Enterprise | custom | — | Everything in Professional plus high availability and clustering, compliance exports and retention policies, AD/LDAP group sync, enterprise search, advanced playbooks, 24x7 support with a 4-hour response target. |
| Enterprise Advanced | custom | — | Everything in Enterprise plus air-gapped deployment workflows, zero-trust attribute-based access, classified-information controls, and scaling to 200,000 concurrent users. |
- Free tier
- Entry hides everything beyond the latest 10,000 channel messages (older ones stay in the database but can't be viewed or searched), has no compliance features, no high availability and no delegated admin roles. Mattermost Team Edition, the MIT-licensed build, is the other free route, for small teams that don't need SSO.
- Billing
- Professional and Enterprise are prepaid annual subscriptions priced per seat; the pricing page doesn't mention monthly billing. One seat covers one activated (not deactivated) user on one server. Admins get a renewal banner 60 days before expiry.
- Hidden costs
- The minimum purchase is more than 10 users, so at least 11 seats. You report activated users every quarter and Mattermost invoices extra seats at current list price, pro rated, with no downward adjustment mid-term. Every server needs its own license, staging servers included. You also run the server yourself (Linux binary plus PostgreSQL, backups, upgrades) or buy Mattermost's hosted option. Single-channel guests are free up to a 1:1 ratio with seats; guests in several channels count as seats.
- Source
- mattermost.com
Also on the list
Related apps
Questions
Mattermost Professional, briefly
Not answered here? Tell us and we'll add it.
Ask a question ›Entry is the free mode of Mattermost Enterprise Edition: self-hosted, with a cap of 10,000 visible channel messages across all channels.
Kinda. The core is a weekend build with the prompt on this page, but real gaps remain: Native iOS and Android apps with a push proxy, and desktop apps, SAML, OpenID Connect and LDAP single sign-on with user sync.
About $10 a month on the Professional plan per seat, $120 a year (checked 2026-10-19).
Native iOS and Android apps with a push proxy, and desktop apps; SAML, OpenID Connect and LDAP single sign-on with user sync; Advanced team permissions, guest access and read-only announcement channels; Boards, playbooks and the Jira, GitHub, GitLab and Teams integrations; Vendor security patches and next-business-day support. If any of those matter to you, keep paying.
Yes: Mattermost Team Edition (open source), Zulip (open source), Rocket.Chat (open source).