In simple English
This tool lets you send emails, receive replies, and run newsletters from your own server. It is an open-source replacement for commercial email services. You keep all your customer data on your own computer or server. It costs you the price of a server and some setup time. You need to handle server maintenance yourself.
What it is
Reloop (an open-source transactional email API and self-hostable Resend alternative) is a complete email infrastructure suite built with TypeScript and Bun (a fast JavaScript runtime environment). It provides an SMTP relay, inbound email parsing, webhooks (automated messages sent to your app when an event occurs), and campaign tools inside a self-hosted package.
What it is good for
Solo builders who want to send app notifications and newsletters without paying expensive monthly fees to third-party services or risking sudden account suspensions.
- Runs entirely on your own hardware with no vendor lock-in.
- Includes both transactional sending and mass marketing campaigns in one place.
- Provides a visual template editor and real-time delivery analytics.
- Custom licence restrictions limit how you can redistribute or resell it as a hosted service.
- Requires a server with Docker and proper DNS configuration for email delivery.
- Managing email deliverability and spam filters takes ongoing maintenance work.
Resend
PostgreSQL
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git clone https://github.com/reloop-labs/reloop.git cd reloop bun setup bun dev