Postmark vs MailerSend
Deliverability-first transactional email versus API plus drag-and-drop template builder.
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 | MailerSend |
|---|---|---|
| DX score | 9/10 | 8/10 |
| SDKs | node, python, go, ruby, php, java, elixir, rust, dotnet | node, python, go, ruby, php |
| Idempotency keys | No | No |
| Operating since | 2010 | 2020 |
| Event stream | Yes | Yes |
| Best published rate per 1,000 | $1.50 | Tiers not published in comparable form |
| Webhooks | Yes | Yes |
| Deliverability | Strong transactional reputation with separate streams for transactional and broadcast traffic, which helps protect sender reputation. | Good and steadily improving; reputation managed via dedicated IP options on paid plans. |
| Free tier | 100/mo developer plan | 500/mo permanent |
For a developer-owned stack running password resets, receipts, and magic links shipped from application code, Postmark takes every priority that separates them here (developer experience, SDK breadth, and operating track record), while MailerSend matches it on the rest. On free tier, Postmark offers 100/mo developer plan against 500/mo permanent from MailerSend. That ordering reflects this audience. Weigh the same table differently and the answer changes.
Side by side
| Feature | Postmark | MailerSend |
|---|---|---|
| DX score | 9/10 | 8/10 |
| SDKs | node, python, go, ruby, php, java, elixir, rust, dotnet | node, python, go, ruby, php |
| Webhooks | Yes | Yes |
| Deliverability | Strong transactional reputation with separate streams for transactional and broadcast traffic, which helps protect sender reputation. | Good and steadily improving; reputation managed via dedicated IP options on paid plans. |
| Free tier | 100/mo developer plan | 500/mo permanent |
| Tagline | Transactional-only, fast and well-delivered. | Modern transactional API with a clean UI. |
| Starts at | $15/mo for 10,000 emails | $7/mo for 5,000 emails |
| 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. | Teams that want both API and visual template editing. |
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
MailerSend
- ›Drag-and-drop templates plus API
- ›Inbound routing supported
- ›Sub-accounts for agencies
- ›Smaller SDK footprint than SendGrid
- ›Brand and ecosystem less recognized than older providers