Roundcube
The standard open-source webmail - your UI over any IMAP provider, with sessions and contacts in your Postgres.
One-click deploy, from $13/mo on a Miget plan.
A webmail client is the honest way to self-host email on a PaaS: the mail server stays wherever deliverability lives (Fastmail, Gmail, your VPS Dovecot), and you own the interface - the part that holds your sessions, contacts, and habits. Roundcube has been the standard for two decades: folders, search, filters, address book, responsive Elastic skin.
This template runs it stateless on a managed Postgres (settings, contacts, caches), behind a thin proxy. Two variables point it at your provider; users log in with their own mailbox credentials.
The deliberately absent piece is stated, not hidden: no SMTP server ships here, because nothing on shared cloud IPs can credibly deliver port-25 mail. Client here, relay where it belongs - the same honest split as the listmonk template.
Upstream project: Roundcube
#what you get
- Full webmail: folders, search, filters, contacts, HTML compose
- Works over any IMAP/SMTP provider (ssl:// and tls:// supported)
- Stateless on managed Postgres - settings and contacts in your DB
- Elastic responsive skin; plugins via env
- GPL, actively maintained official image
- Pairs with mailpit (dev) and listmonk (sending) for the full mail lane
#topology
| Service | Role | Public |
|---|---|---|
| roundcube | webmail (:80, fixed) | no |
| web | nginx :5000 -> roundcube:80 | yes |
| db | Postgres - managed service on Miget, container locally | no |
#miget sizing
// this stack needs
1.6 GiB RAM · 5 GB disk · 3 services
PHP with a 128M limit per worker - 512 MiB carries a team. The managed Postgres holds everything worth keeping.
Hobby - recommended fit
$13/mo
1 vCPU · 2 GiB · 50 GiB disk
Headroom for your own apps: 2 GiB at $19/mo
Professional - production
$22/mo
1 vCPU · 2 GiB · 10 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. other PaaS
Estimated monthly cost of running this exact stack (1.6 GiB RAM, 5 GB disk, 3 containers) elsewhere, from published June 2026 rates.
| Platform | Est. monthly | Notes |
|---|---|---|
| Miget ★ | $13 flat | compose stacks first-class: one deploy, dedicated vCPU, managed Postgres/Valkey, volumes and TLS all included in the plan |
| Heroku | ~$81 | no volumes; nothing between 1 GB ($50) and 2.5 GB ($250) dynos - 2 GB containers cost far more than shown |
| DO App Platform | ~$25 | no persistent volumes - stateful containers need managed DBs/Spaces (base $5 Spaces included here) |
| Render | ~$22 | per-service instances (0.5 GB $7, 2 GB $25) - every container is its own paid service |
| Railway | ~$17 | usage-based ($10/GB RAM-mo); vCPU billed separately at $20/vCPU-mo on top |
| Fly.io | ~$10 | 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
roundcube -
Set the required variables:
IMAP_HOST, e.g. ssl://imap.fastmail.comSMTP_SERVER, e.g. tls://smtp.fastmail.com (the provider’s submission server)
- 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/roundcube
docker compose up -dSame files, same behavior. The template README covers connection strings and scaling notes.
#faq
Does this replace Fastmail or Google Workspace?
It replaces their web INTERFACE, not their servers: you keep paying ~$5-7/user for the mailbox and deliverability, while the UI, session data, and contacts live on your infrastructure. Full mail-server self-hosting needs port 25 and IP reputation no shared platform can offer - this split is the honest one.
Can different users connect different providers?
The template sets one default IMAP host - right for a team on one provider. Multi-host setups go in a mounted config; for a true multi-account aggregator UX, Cypht is the upstream alternative worth a look.
Does Gmail work?
Yes, with an app password (or OAuth via plugin configuration): imap.gmail.com over ssl:// and smtp.gmail.com over tls://. Workspace accounts behave the same.
Ship Roundcube today
One compose stack, 1.6 GiB of RAM, from $13/month flat, and it runs on your laptop with the same files.