Open-source alternatives to SendGrid
SendGrid relays transactional and bulk mail through its own servers. The list below is every catalog tool tagged Communication - Email - Mail Transfer Agents, which is the closest the catalog gets to the same job; none of them has been checked feature by feature against SendGrid.
| Tool | Stars |
|---|---|
Fast, highly extensible, and event driven SMTP server. MIT · released 2026-09-05 | 5,615 |
Secure SMTP server implementation from the OpenBSD project. ISC · released 2026-03-26 | 582 |
A small MTA for home and office use. Works on Linux and FreeBSD. BSD-3-Clause · released unknown | 264 |
Fast, scalable, enterprise mail/groupware server providing ESMTP, IMAP, POP3, webmail, mailing list, basic web-based calendaring and scheduling services. GPL-3.0 · released unknown | n/a |
A small and easy to configure SMTP and POP3 server for Windows and Linux. GPL-3.0 · released unknown | n/a |
Message transfer agent (MTA) developed at the University of Cambridge. GPL-3.0 · released unknown | n/a |
Fast, easy to administer, and secure Sendmail replacement. IPL-1.0 · released unknown | n/a |
Message transfer agent (MTA). Sendmail · released unknown | n/a |
SMTP (email) server with a focus on simplicity, security, and ease of operation. Apache-2.0 · released unknown | n/a |
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