Sending transactional and marketing email from web apps.
Sending APIs (free tier)
- ★ Resend — TypeScript-first, React Email native, ~3000/month free. The default for new TS projects.
- Postmark — gold standard for deliverability; has a free trial, then paid.
- SendGrid (Twilio) — large, mature; small free tier (~100/day).
- Mailgun — small free tier; mature.
- Amazon SES — cheap at scale; less ergonomic SDK.
- Brevo (formerly Sendinblue), Mailtrap, MailerSend — varying free tiers.
Authoring transactional email
- ★ React Email — write email as React components; render to HTML. Free, open source. Pairs beautifully with Resend.
- MJML — markup language designed for email; reliable across clients.
- maily.to — Tiptap-based email editor; OSS.
- Mosaico — open-source drag-and-drop email designer.
Local dev / inboxes
- Mailpit — single-binary local SMTP + web UI for previewing emails in dev.
- Mailhog — older, similar.
- Ethereal Email — fake SMTP for tests.
Marketing / lifecycle
- Loops — modern, free tier; transactional + marketing.
- Customer.io — lifecycle email; powerful, paid.
- Listmonk — open-source self-hosted newsletter platform.
Lower-level
- Nodemailer — the classic Node SMTP library; still huge.
@cloudflare/email— Workers-friendly email send.
Pick this if…
- Default transactional, TS-first: Resend + React Email.
- Need maximum deliverability and budget: Postmark.
- At AWS scale: SES.
- Self-host newsletters: Listmonk.
- You only have an SMTP server: Nodemailer.