Postmark vs Mailgun
Transactional deliverability specialist versus flexible developer email infrastructure.
What matters for growth and lifecycle teams
Growth work lives or dies on targeting and measurement. What matters is whether behavioral triggers can be built without engineering time, whether the event stream supports attribution past the open, and whether deliverability holds when broadcast volume shares a reputation with product email.
| Priority | Postmark | Mailgun |
|---|---|---|
| Scheduling | No | Yes |
| Event stream | 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. |
| Operating since | 2010 | 2010 |
| Suppressions API | Yes | Yes |
| Best published rate per 1,000 | $1.50 | $0.70 |
| Multi-tenant | Yes | Yes |
| Free tier | 100/mo developer plan | 100/day permanent free plan |
| Starts at | $15/mo for 10,000 emails | $15/mo for 10,000 emails (Basic) |
For lifecycle and activation work running behavior-triggered journeys, broadcasts, and winback campaigns measured on revenue, Mailgun takes every priority that separates them here (scheduling and best published rate per 1,000), while Postmark matches it on the rest. 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 |
|---|---|---|
| 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. |
| Multi-tenant | Yes | Yes |
| Free tier | 100/mo developer plan | 100/day permanent free plan |
| Starts at | $15/mo for 10,000 emails | $15/mo for 10,000 emails (Basic) |
| Tagline | Transactional-only, fast and well-delivered. | Developer-leaning email infra, owned by Sinch. |
| Pricing model | tiered | tiered |
| API | Yes | Yes |
| SMTP | Yes | Yes |
| SDKs | node, python, go, ruby, php, java, elixir, rust, dotnet | node, python, go, ruby, php, java |
| Templates | rich | rich |
| React Email | No | No |
| Webhooks | Yes | Yes |
| Inbound | Yes | Yes |
| Idempotency | No | No |
| Dedicated IP | Yes | Yes |
| DX score | 9/10 | 7/10 |
| 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