Best deliverability
Ranked on independent inbox-placement tests over the past two years.
criteria
- Independent inbox-placement scores
- Reputation management tooling
- Stream separation
- 01
Amazon SES
TransactionalAWS-grade infrastructure, regional reputation pools, and the volume that keeps shared IPs warm. The default backbone for high-deliverability transactional sending once configured and warmed.
- 02
Postmark
TransactionalConsistently in the top tier across independent tests. Stream separation keeps transactional reputation insulated from broadcast.
- 03
SendGrid
Transactional MarketingTwilio-backed, broad ecosystem, and dedicated IP options that let high-volume senders manage their own reputation. Shared pool varies, dedicated pool performs.
- 04
SMTP2GO
TransactionalRepeatedly recognized for top inbox placement.
- 05
Mailtrap
Transactional TestingStrong recent results.
- 06
Mailgun
TransactionalGood, with reputation tooling on higher tiers.
All 6 compared
Every provider in this ranking against the priorities developers picking email infrastructure weigh. Free tier and entry price sit with each pick above.
| Provider | DX score | SDKs | Idempotency keys | Operating since | Event stream | Best published rate per 1,000 | Webhooks |
|---|---|---|---|---|---|---|---|
| Amazon SES | 4/10 | node, python, go, ruby, php, java, rust, dotnet | No | 2011 | Yes | $0.10 | No |
| Postmark | 9/10 | node, python, go, ruby, php, java, elixir, rust, dotnet | No | 2010 | Yes | $1.50 | Yes |
| SendGrid | 6/10 | node, python, go, ruby, php, java, dotnet | No | 2009 | Yes | $0.40 | Yes |
| SMTP2GO | 7/10 | node, python, go, ruby, php | No | 2006 | Yes | Tiers not published in comparable form | Yes |
| Mailtrap | 8/10 | node, python, go, ruby, php, elixir | No | 2014 | Yes | Tiers not published in comparable form | Yes |
| Mailgun | 7/10 | node, python, go, ruby, php, java | No | 2010 | Yes | $0.70 | Yes |
If you are developers picking email infrastructure
The question here is which one a backend engineer would rather operate. That means SDK depth in the language already in use, whether a retry can safely be replayed, how much the event log tells you when a customer says the email never arrived, and whether the pricing curve stays sane as volume grows.
The order above is the general editorial ranking. Re-sorted against developer experience, SDK breadth, and idempotency keys, the shortlist for password resets, receipts, and magic links shipped from application code becomes Postmark, SendGrid, and SMTP2GO. That differs from the headline order, which weighs all audiences together.
the long version
Transactional Email APIs With the Best Deliverability
A reliability-first ranking for password resets, magic links, receipts, billing notices, and account security email.