About Relais

What is Relais

Relais is an open-source platform that connects your custom domain email to Gmail. It receives inbound email on a dedicated mail server and delivers it directly to your Gmail inbox using the Gmail API. Outbound email works through Gmail's Send As feature with per-domain SMTP credentials.

Why we built it

The existing options for custom domain email in Gmail aren't great. Google Workspace starts at $7/month per user. Gomailify works but costs $6/year minimum and is closed-source with vendor lock-in. We wanted something simple, affordable, and open.

How it's built

Relais is a single Next.js application deployed on Vercel with a self-hosted Stalwart mail server for SMTP. The entire codebase is TypeScript. Delivery is handled by Vercel Workflow for durability and automatic retries.

Open source

The full source code is available on GitHub under the GPL license. You can self-host the entire platform with your own mail server. The managed version at relais.sh exists for people who don't want to deal with server setup.

Built by

Relais is built by Adrian Lam.