Best free tier for transactional

Developer-first transactional email with React Email templates and a clean API — 3,000 emails/month (100/day) free forever with 1 custom domain and full DKIM/SPF setup.

Bandwidth

n/a

Requests

3,000 emails/month (100/day), 1 custom domain

Paid from

$20/mo

High-deliverability transactional email — 100 emails/month free forever after a 30-day trial, with separate transactional + broadcast streams and SMTP relay + API.

Bandwidth

n/a

Requests

100 emails/month free forever (after 30-day trial)

Paid from

$15/mo

Twilio SendGrid — 100 emails/day (3,000/month) free forever with SMTP relay + API, plus marketing-campaign tools on paid plans. Battle-tested at scale.

Bandwidth

n/a

Requests

100 emails/day (3,000/month) free forever

Paid from

$20/mo

Mailgun — 5,000 emails/month free for the first 3 months, then pay-as-you-go (no forever-free tier). Robust REST API, inbound routing, and email validation.

Bandwidth

n/a

Requests

5,000 emails/month free for first 3 months, then pay-as-you-go

Paid from

$15/mo