Postmark
Transactional-only email API with the strongest independently-tested deliverability of any platform reviewed — the tradeoff is highest cost per email.
How we testPostmark deliberately refuses to send marketing/bulk email on the same infrastructure as transactional mail, and enforces that at the account-approval stage. That focus is the whole pitch: keeping their shared IP pools clean of newsletter/blast traffic is what drives their deliverability numbers. It's priced as a premium for that guarantee rather than competing on cost.
Pros
- +Best independently-tested inbox placement of the group: 83.3% inbox / 1.0% spam vs. 77.1%/20.0% for Amazon SES
- +Transactional-only focus means no risk of a marketing sender tanking your reputation
- +Strong reputation for developer experience and support
Cons
- −Most expensive per email at low-to-mid volume of any provider reviewed
- −Account approval process can restrict use cases that look like marketing/bulk
- −Whitelist/blacklist controls are comparatively less granular than SMTP2GO’s
Pricing
Developer (free)
$0/mo · annual commitment
Month-to-month: not published
- ✓100 emails/mo
Basic
$15/mo · annual commitment
Month-to-month: not published
- ✓10,000 emails/mo
Platform
$18/mo · annual commitment
Month-to-month: not published
- ✓10,000 emails/mo, lowest per-email rate
Specifications
| Rating | 4.4 |
| Inbox rate (3rd-party) | 83.3% |
| Automation Builder | No |
| Dedicated IP | ✓ |
| A/B Testing | No |
Researched and drafted with AI assistance; reviewed and approved by Tim Meredith. How we use AI