Resend vs Mailgun vs Postmark: free email API plans compared
Short version: Resend gives the most free sending, 3,000 emails a month (100 a day) across 3 domains. Mailgun Free also allows 100 emails a day, with 1 custom sending domain and 1 day of logs. Postmark's Developer plan is for testing: 100 emails a month that never expire, no card. SendGrid now offers only a 60-day trial.
| Tool | What you get | Limits | Card required | The catch | Source |
|---|---|---|---|---|---|
| Resend | 3,000 emails a month, 3 domains, ticket support. | 100 emails/day | Vendor doesn't say | 100 emails a day cap. | resend.com/pricing checked 2026-10-28 |
| Mailgun | Transactional email API and SMTP relay with 100 emails a day, tracking, webhooks and 1 custom sending domain. | 100 emails/day; 1 custom sending domain; 2 API keys; 1 inbound route; 1-day log retention; 1 user | Vendor doesn't say | Capped at 100 emails a day, logs are kept 1 day, and only 1 user is allowed. | mailgun.com/pricing checked 2026-10-28 |
| Postmark | 100 emails a month to test the integration. | 100/month | No (stated by vendor) | No overages allowed; 100 emails a month only. | postmarkapp.com/pricing checked 2026-10-28 |
Every row is taken from the vendor's official pricing page, checked 2026-10-28. "Vendor doesn't say" means the official page does not mention it. Plans change, so confirm on the vendor's site.
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FAQ
Does SendGrid still have a free plan?
No. Twilio SendGrid's Email API pricing page lists a Free Trial at $0 a month for 60 days that sends 100 emails a day, with no credit card; after that you need a paid plan, starting with Essentials at $19.95 a month (twilio.com/en-us/products/email-api/pricing, checked 2026-10-28). That is why SendGrid is not in this table.
Which free email API sends the most?
Resend: 3,000 emails a month on the Free plan, capped at 100 a day. Mailgun Free also caps at 100 emails a day. Postmark's Developer plan allows 100 emails a month with no overages (all checked 2026-10-28).
Does Postmark's free plan expire?
No. Postmark says everyone starts on the free Developer plan with 100 emails every month, and it never expires or runs out (checked 2026-10-28).
How many domains can I send from for free?
Resend Free includes 3 domains; Mailgun Free includes 1 custom sending domain. Postmark's pricing page does not give a domain limit for the Developer plan.
Do they need a credit card?
Postmark's pricing page says no credit card is required. Resend's and Mailgun's pricing pages don't say either way.