Mattermost
Open-source team chat - channels, threads, calls, integrations - on one managed Postgres, no per-seat bill.
One-click deploy, from $25/mo on a Miget plan.
Team chat is the purest per-seat tax: Slack Pro is $8.75/user/month, Teams Essentials $4, and the bill grows with every hire. Mattermost is the open-source escape - channels, threads, DMs, voice/video calls, slash commands, integrations, and a plugin marketplace, with your messages on your infrastructure.
This template runs Team Edition on a single plain managed Postgres (no replica set, no Redis) and listens on :5000 directly - no proxy. Config, uploads, plugins, and the search index persist on volumes.
It is the catalogue’s default team-chat pick precisely because it is operationally boring: one app, one managed database. (Rocket.Chat is here too, for teams who want its apps marketplace and accept running a MongoDB replica set.)
Upstream project: Mattermost (Team Edition)
#what you get
- Channels, threads, DMs, and group messaging
- Voice/video calls, screen share (calls plugin)
- Slash commands, webhooks, bots, and a plugin marketplace
- Desktop + mobile apps; SSO via the catalogue’s IdP templates
- Single plain managed Postgres - no replica set, no Redis
- Team Edition image is MIT-licensed
#topology
| Service | Role | Public |
|---|---|---|
| mattermost | server + API (:5000) | yes |
| db | Postgres - real container locally, **managed Postgres on Miget** | no |
#miget sizing
// this stack needs
3 GiB RAM · 30 GB disk · 2 services
2 GiB carries up to ~1,000 users per upstream guidance. Uploads and the search index are the volume growth; the managed Postgres holds messages.
Hobby - recommended fit
$25/mo
2 vCPU · 4 GiB · 80 GiB disk
Headroom for your own apps: 8 GiB at $49/mo
Professional - production
$85/mo
4 vCPU · 8 GiB · 50 GiB disk
Dedicated resources, production SLOs - plan details
One Miget plan is a fixed pool of compute - the whole stack (managed databases included) deploys inside it, and anything left over runs your other apps. No per-service or per-seat math.
#vs. the managed service
What the hosted equivalents charge, against the flat Miget plan this stack fits on. Prices as of June 2026, sources linked.
| Service | Plan | Monthly | What you get |
|---|---|---|---|
| Mattermost on Miget ★ | 4 GiB plan | $25 | this whole stack, flat - no usage meters, and room left for your own apps |
| Slack | Pro | ~$219 | $8.75/user/mo (monthly) at 25 users; $7.25 annual |
| Microsoft Teams | Essentials | ~$100 | $4/user/mo (annual) at 25 users |
Team chat is per-seat everywhere; Mattermost self-hosted has no seat meter.
#vs. other PaaS
Estimated monthly cost of running this exact stack (3 GiB RAM, 30 GB disk, 2 containers) elsewhere, from published June 2026 rates.
| Platform | Est. monthly | Notes |
|---|---|---|
| Miget ★ | $25 flat | compose stacks first-class: one deploy, dedicated vCPU, managed Postgres/Valkey, volumes and TLS all included in the plan |
| Heroku | ~$150 | no volumes; nothing between 1 GB ($50) and 2.5 GB ($250) dynos - 2 GB containers cost far more than shown |
| Render | ~$45 | per-service instances (0.5 GB $7, 2 GB $25) - every container is its own paid service |
| DO App Platform | ~$41 | no persistent volumes - stateful containers need managed DBs/Spaces (base $5 Spaces included here) |
| Railway | ~$35 | usage-based ($10/GB RAM-mo); vCPU billed separately at $20/vCPU-mo on top |
| Fly.io | ~$22 | cheapest sticker price - but burstable shared CPUs (1/16 core; dedicated vCPUs cost ~2-3×), no compose deploys (one app per container, manual wiring), managed DBs billed extra |
Estimates assume RAM fully allocated at published on-demand rates - and sticker price isn't the whole comparison: the cheaper rows buy burstable shared CPUs, per-service wiring instead of a compose deploy, and managed databases billed separately. Heroku and DO App Platform have no persistent volumes at all - stateful stacks like this one need workarounds there.
#deploy it
On Miget
- Create a Compose Stack in app.miget.com pointing at the templates repository
- Set the stack path to
mattermost -
Set the required variable:
MM_SITE_URL, the app’s https domain after first deploy
- Deploy. Miget layers
compose.miget.yaml(RAM, privacy, volumes, managed services) automatically
Locally first?
Every template is portable, vanilla Docker Compose - the Miget overrides are ignored locally:
git clone https://github.com/deployable-sh/stacks
cd miget-compose-templates/mattermost
docker compose up -dSame files, same behavior. The template README covers connection strings and scaling notes.
#faq
How does it compare to Slack or Teams on cost?
Slack Pro is $8.75/user/month, Teams Essentials $4 - a 25-person team is $100-220/month forever. Mattermost here is $25/month flat with unlimited users, and the conversation history lives in a Postgres you control.
Mattermost or Rocket.Chat?
Both are in this catalogue. Mattermost is the simpler deploy - one plain managed Postgres, no replica set. Rocket.Chat needs a MongoDB replica set (the mongodb template) but brings an apps marketplace and omnichannel. Default to Mattermost unless you specifically want Rocket.Chat’s extras.
Can I add SSO?
Yes - Mattermost supports OIDC/SAML (GitLab-style and enterprise providers); point it at the catalogue’s keycloak, authentik, zitadel, or logto templates. Team Edition covers the common cases; some enterprise auth features live in paid tiers.
Ship Mattermost today
One compose stack, 3 GiB of RAM, from $25/month flat, and it runs on your laptop with the same files.