Postmark vs Mailgun
Transactional deliverability specialist versus flexible developer email infrastructure.
What matters for 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.
| Priority | Postmark | Mailgun |
|---|---|---|
| DX score | 9/10 | 7/10 |
| SDKs | node, python, go, ruby, php, java, elixir, rust, dotnet | node, python, go, ruby, php, java |
| Idempotency keys | No | No |
| Operating since | 2010 | 2010 |
| Event stream | Yes | Yes |
| Best published rate per 1,000 | $1.50 | $0.70 |
| Webhooks | Yes | Yes |
| Deliverability | Strong transactional reputation with separate streams for transactional and broadcast traffic, which helps protect sender reputation. | Generally good, with deliverability monitoring tools available on higher tiers. Inbound routes and suppressions are battle-tested. |
| Free tier | 100/mo developer plan | 100/day permanent free plan |
For a developer-owned stack running password resets, receipts, and magic links shipped from application code, Postmark takes developer experience and SDK breadth, while Mailgun takes best published rate per 1,000. On free tier, Postmark offers 100/mo developer plan against 100/day permanent free plan from Mailgun. That ordering reflects this audience. Weigh the same table differently and the answer changes.
Side by side
| Feature | Postmark | Mailgun |
|---|---|---|
| DX score | 9/10 | 7/10 |
| SDKs | node, python, go, ruby, php, java, elixir, rust, dotnet | node, python, go, ruby, php, java |
| Webhooks | Yes | Yes |
| Deliverability | Strong transactional reputation with separate streams for transactional and broadcast traffic, which helps protect sender reputation. | Generally good, with deliverability monitoring tools available on higher tiers. Inbound routes and suppressions are battle-tested. |
| Free tier | 100/mo developer plan | 100/day permanent free plan |
| Tagline | Transactional-only, fast and well-delivered. | Developer-leaning email infra, owned by Sinch. |
| Starts at | $15/mo for 10,000 emails | $15/mo for 10,000 emails (Basic) |
| Pricing model | tiered | tiered |
| API | Yes | Yes |
| SMTP | Yes | Yes |
| Templates | rich | rich |
| React Email | No | No |
| Inbound | Yes | Yes |
| Multi-tenant | Yes | Yes |
| Idempotency | No | No |
| Dedicated IP | Yes | Yes |
| Best for | Teams where password resets, receipts, and magic links absolutely cannot miss the inbox. | Technical teams that want SMTP relay plus advanced routing. |
Postmark
- ›Transactional-only routing and strong operational history
- ›Streams cleanly separate transactional and broadcast
- ›Free DMARC monitoring product (dmarc.postmarkapp.com)
- ›Retains full message content and metadata for 45 days for debugging
- ›No idempotency keys
- ›Pricing per email is higher than SES, Mailgun, or SMTP2GO
- ›No drag-and-drop template builder
- ›Marketing automation is intentionally absent
Mailgun
- ›Strong SMTP relay support, useful when migrating off self-hosted Postfix
- ›Inbound routes with regex matching
- ›Validation and parsing tools available
- ›Sub-accounts for agency use cases
- ›Overage pricing and plan differences need close review at scale
- ›Documentation is comprehensive but occasionally out of date
- ›No idempotency keys
- ›Sinch ownership has moved focus toward enterprise