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 Postmark if you want the longest message history, or you send about 10,000 a month; choose SendGrid if you send 50,000 to 100,000 a month and want the lower list price. On list prices as of September 2026: at 10,000 Postmark lists lower ($15 against $19.95); at 50,000 SendGrid lists lower ($19.95 against $55); at 100,000 SendGrid lists lower ($34.95 against $115); at 500,000 Postmark lists lower ($455 against $499). 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 | Postmark | SendGrid | Warmerly |
|---|---|---|---|
| 10,000 | $15Basic 10k | $19.95Essentials 50k | $15Starter |
| 50,000 | $55Basic 50k | $19.95Essentials 50k | $15Starter |
| 100,000 | $115Basic 125k | $34.95Essentials 100k | $29Growth |
| 500,000 | $455Basic 700k | $499Pro 700k | $279Scale 500k |
List prices, monthly billing, USD: the cheapest published plan that includes that many emails, overage left out. Prices from postmarkapp.com and sendgrid.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 | Postmark | SendGrid | Warmerly |
|---|---|---|---|
| API shape | REST, POST /email with PascalCase fields; server token header | REST v3 /mail/send with a personalizations array; bearer key | REST, JSON over HTTPS, bearer key, Idempotency-Key header |
| SMTP relay | Yes | Yes | Not yet (on the roadmap) |
| Delivery webhooks | Yes | Event Webhook: 2 on Essentials, 5 on Pro | Not yet. Read each email's delivery timeline from GET /emails/{id} |
| Templates | Yes | Yes (dynamic templates) | Not yet. You send your own HTML and text |
| Dedicated IP | From $50/mo, for 300,000+ emails a month on Pro or higher | 1 included on Pro and Premier | $29/mo on Scale plans |
| Suppression list | Automatic on hard bounce and spam complaint, per message stream | Yes: bounce, spam report and unsubscribe lists | Automatic on hard bounce and spam complaint, shared with Warmerly outreach |
| Free tier | 100 emails a month | 100 a day for 60 days (a trial) | 5,000 a month (200 a day), no time limit, no card |
| Log retention | 45 days; up to 365 on Pro and Platform (add-on from $5/mo) | Email activity: 3 days on Essentials, 7 on Pro | Content 30 days; the email record and its delivery events are kept |
| SDKs | Official libraries for several languages (see postmarkapp.com) | Official libraries for C#, Go, Java, Node.js, PHP, Python and Ruby | None. One HTTP request from any language |
| Support | See postmarkapp.com | See sendgrid.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 Postmark alternative and SendGrid alternative pages.
On list prices as of September 2026: at 10,000 Postmark lists lower ($15 against $19.95); at 50,000 SendGrid lists lower ($19.95 against $55); at 100,000 SendGrid lists lower ($34.95 against $115); at 500,000 Postmark lists lower ($455 against $499). Overage rates and plans larger than those compared are not included, so check each vendor's pricing page for your exact volume.
Postmark: 100 emails a month. SendGrid: 100 a day for 60 days (a trial).
Postmark: Yes. SendGrid: Yes.
Postmark: 45 days; up to 365 on Pro and Platform (add-on from $5/mo). SendGrid: Email activity: 3 days on Essentials, 7 on Pro.
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 Postmark alternative and SendGrid 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.
