Warming up
Every account now comes with a free mailbox — warmed automatically, no domain to buy. See how it works
Transactional email API
Every account now comes with a free mailbox — warmed automatically, no domain to buy. See how it works
Choose Resend if you send more than 10,000 a month and want the lower list price and a bigger free plan; choose Postmark if you want longer message history and inbound processing. On list prices as of September 2026: at 10,000 Postmark lists lower ($15 against $20); at 50,000 Resend lists lower ($20 against $55); at 100,000 Resend lists lower ($35 against $115); at 500,000 Resend lists lower ($350 against $455). Prices are the cheapest published monthly plan that covers each volume, with overage left out.
What each one lists for the same monthly volume, from their own pricing pages.
| Emails a month | Resend | Postmark | Warmerly |
|---|---|---|---|
| 10,000 | $20Pro 50k | $15Basic 10k | $15Starter |
| 50,000 | $20Pro 50k | $55Basic 50k | $15Starter |
| 100,000 | $35Pro 100k | $115Basic 125k | $29Growth |
| 500,000 | $350Scale 500k | $455Basic 700k | $279Scale 500k |
List prices, monthly billing, USD: the cheapest published plan that includes that many emails, overage left out. Prices from resend.com and postmarkapp.com as of September 2026; check their sites for current rates. Shaded cells are the cheaper of the two; Warmerly is shown for reference.
What each one does today. Warmerly is a third option for API-only app email; where it says "not yet", it means it.
| Feature | Resend | Postmark | Warmerly |
|---|---|---|---|
| API shape | REST, JSON over HTTPS, bearer key, Idempotency-Key header | REST, POST /email with PascalCase fields; server token header | REST, JSON over HTTPS, bearer key, Idempotency-Key header |
| SMTP relay | Yes (smtp.resend.com) | Yes | Not yet (on the roadmap) |
| Delivery webhooks | Yes: 5 endpoints on Pro, 10 on Scale | Yes | Not yet. Read each email's delivery timeline from GET /emails/{id} |
| Templates | Yes, sent by template id with variables | Yes | Not yet. You send your own HTML and text |
| Dedicated IP | $30/mo add-on on Scale | From $50/mo, for 300,000+ emails a month on Pro or higher | $29/mo on Scale plans |
| Suppression list | Automatic on hard bounce and spam complaint | Automatic on hard bounce and spam complaint, per message stream | Automatic on hard bounce and spam complaint, shared with Warmerly outreach |
| Free tier | 3,000 a month (100 a day) | 100 emails a month | 5,000 a month (200 a day), no time limit, no card |
| Log retention | 30 days on Free; see resend.com for paid plans | 45 days; up to 365 on Pro and Platform (add-on from $5/mo) | Content 30 days; the email record and its delivery events are kept |
| SDKs | Official SDKs for Node.js, Python, PHP, Ruby, Go, Rust, Java, .NET and Elixir | Official libraries for several languages (see postmarkapp.com) | None. One HTTP request from any language |
| Support | Ticket support; a dedicated Slack channel on Scale | See postmarkapp.com | Email (support@warmerly.com), plus a 99.9% monthly uptime commitment with service credits |
Neither is right for everyone. These are the cases that decide it.
Warmerly sends through Amazon SES and keeps transactional mail apart from cold outreach. It has a free plan of 5,000 emails a month, but it is REST only today: no SMTP relay, delivery webhooks or templates yet. If an API is all you need, see how it compares on the Resend alternative and Postmark alternative pages.
On list prices as of September 2026: at 10,000 Postmark lists lower ($15 against $20); at 50,000 Resend lists lower ($20 against $55); at 100,000 Resend lists lower ($35 against $115); at 500,000 Resend lists lower ($350 against $455). Overage rates and plans larger than those compared are not included, so check each vendor's pricing page for your exact volume.
Resend: 3,000 a month (100 a day). Postmark: 100 emails a month.
Resend: Yes (smtp.resend.com). Postmark: Yes.
Resend: 30 days on Free; see resend.com for paid plans. Postmark: 45 days; up to 365 on Pro and Platform (add-on from $5/mo).
Warmerly is a transactional email API that sends through Amazon SES. It lists $15 a month for 50,000 emails and a free plan of 5,000 emails a month, but it is REST only and has no SMTP relay, webhooks or templates yet. Compare it on the Resend alternative and Postmark alternative pages.
Create a free account, verify a sending domain and send a test from the dashboard. 5,000 emails a month free, no card.
