What is the best open-source alternative to SendGrid?

The best open-source alternative to SendGrid depends on the use case. The highest-PopScore candidates on GitPop are postal, maddy, mail-server.

Is SendGrid open source?

No, SendGrid is a closed-source product by Twilio, Inc.. The open-source alternatives on this page are listed by GitPop PopScore (momentum, activity, and noise-filtered).

3 candidates

Open source alternatives to SendGrid

Email delivery platform for transactional and marketing emails. · Twilio, Inc.

Pricing: Free up to 100 emails/day; paid from $20/mo

SendGrid (Twilio) and Postmark are the default managed email-delivery services. The open-source path is to self-host a transactional email stack: Maddy (modern all-in-one SMTP+IMAP), Postal (full marketing/transactional like SendGrid), or Stalwart SMTP (high-performance mail server). For marketing/transactional hybrid, Postal is the most direct SendGrid replacement; for developer-first transactional email, Maddy is the right pick.

The 3 candidates, ranked by PopScore

#01postal/postal
Self-hostable full email delivery platform. The most direct SendGrid replacement in 2026, with marketing and transactional pipelines.
GitHub
#02foxcpp/maddy
All-in-one SMTP, IMAP, and DKIM server written in Go. The right pick for 'I just need a self-hostable mail server that doesn't hate me'.
GitHub
#03stalwartlabs/mail-server
High-performance mail server with JMAP, IMAP4, and SMTP. The right pick for teams that want a modern, Rust-native replacement for Postfix/Dovecot.
GitHub

Related alternatives

Looking for a side-by-side comparison of two open-source projects? The compare matrix has 60+ "X vs Y" pages. Looking for a curated "best of" list for a specific category? See Best AI tools 2026 (and the 7 other category editions).