Requirements

The short list

• A Linux server with Docker and the Compose plugin: 2 vCPUs and 4 GB of RAM to start.
• A domain or subdomain whose A or AAAA record points at it.
• Ports 80 and 443 open to the internet.

Everything else on this page is optional. When you have these, run the install script.

Server

• Linux on amd64 or arm64. macOS works for trying it out with Docker Desktop. On Windows, run it inside WSL with Docker Desktop.
• Docker with the Compose plugin. The installer offers to install Docker on Linux if it is missing.
• Memory and disk: as a starting point for a small team, plan for 2 vCPUs and 4 GB of RAM, then size from what you observe. Disk grows with email and attachments, so start with at least 20 GB and watch it, or move attachments to object storage.

Network

• A domain (or subdomain) with an A/AAAA record pointing at the server, such as desk.example.com.
• Ports 80 and 443 open, so Caddy can obtain and renew a certificate and serve HTTPS.
• Outbound access to your mail providers (IMAP 993, SMTP 465 or 587) and to Google and Microsoft if you connect those mailboxes.
• Optional: port 25 open and an MX record if you want to receive forwarded mail directly on this server. See Email setup.

Optional services

For	You need
Password resets, invitations, verification email	An SMTP server, or Amazon SES. See Email setup.
One-click Google or Microsoft mailboxes and sign-in	Your own OAuth apps. See Google and Microsoft OAuth.
Attachments outside the server	S3, Cloudflare R2 or MinIO. See Storage.
Bot protection on sign-in	A Cloudflare Turnstile site key and secret.
A managed database	Any Postgres, including Neon. See Postgres and Neon.