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Postmark alternatives

Four email services a developer leaving Postmark would actually consider, weighed on inbound mail, signed webhooks, agent tooling and what an extra thousand emails costs. Every figure was read from the vendor's own page on 2026-10-17.

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Postmark
Postmark is a transactional email service with six official libraries, an SMTP option and Message Streams, which keep transactional and broadcast mail on separate sending infrastructure.
What this page is
A list of four email services that would take the mail Postmark sends for you today, compared on the same rows and against the same sources. Rasket is one of them, and we build it — so every claim we make about ourselves is linked to a Rasket page, and every claim about anybody else is linked to theirs.

Key takeaways

  • Extra emails, per 1,000 — Rasket: $0.60. Postmark: $1.80.
  • Entry paid plan — Rasket: $20 a month for 50,000 emails. Postmark: $15 a month for 10,000 emails.
  • Free plan — Rasket: 3,000 emails a month, 100 emails a day, 3 domains. Postmark: 100 emails a month, and it does not expire.
  • Inbound email — Rasket: Yes. Postmark: On the Pro and Platform plans.
  • Official SDKs — Rasket: Coming soon. Postmark: Node.js and TypeScript, Python, Ruby, PHP, Java and .NET.

Why developers look for a Postmark alternative

Three reasons that are rows of the table below rather than opinions. Each one is something Postmark publishes about itself.

  • Their documentation states that Postmark does not sign webhooks with HMAC, so a receiver authenticates the sender some other way.
  • Fifty thousand emails is $55 a month on Basic, and extra mail is $1.80 per thousand.
  • Inbound email processing is listed against the Pro and Platform plans, not the entry one.

None of those is a reason on its own. They are reasons if they describe what you are doing: a product past its free tier, a support conversation longer than the history you can read, a campaign you would rather not buy twice.

Four alternatives to Postmark

Rasket is first because we build it, and you should read the table before you take our word for the order.

  1. 1.Rasket

    Yes, and the webhook row is the reason most teams look. Postmark's documentation states that they do not support HMAC signatures on webhooks; Rasket signs every event and you can replay one from the dashboard. Rasket also includes inbound mail on every plan and charges $0.60 per extra thousand against $1.80 on Basic. Postmark keeps history longer by default — 45 days against 30 — and publishes six client libraries where Rasket's are not out yet, so weigh those before moving.

    Best for: Products that send campaigns and receive replies as well as sending receipts

  2. 2.Mailgun

    Mailgun is an email API from Sinch with six official SDKs, an SMTP relay, rule-based inbound routing and signed webhooks, sold on plans whose log retention grows with the tier. Free plan: 100 emails a day. Extra emails, per 1,000: From $1.80 on Basic.

    Best for: Teams who route inbound mail with rules and want a relay in front of it

  3. 3.MailerSend

    MailerSend is an email API with seven official libraries, an SMTP relay, signed webhooks, inbound routing and an MCP server, sold on small plans that start below every other entry price here. Free plan: 500 emails a month, 1 domain, 1 template. Extra emails, per 1,000: $0.90 on Starter and Professional.

    Best for: Small projects that want the cheapest paid plan on this list

  4. 4.Brevo

    Brevo is a marketing platform with a transactional email API attached: an SMTP relay, seven official SDKs, authenticated webhooks, inbound parsing, idempotency keys for batch sends and an MCP server. Free plan: 300 emails a day. Extra emails, per 1,000: No per-1,000 rate: email volume is bought in steps.

    Best for: Teams who want marketing, CRM and transactional email from one vendor

The four, row by row

The same rows for all four, with the source of every cell numbered at the foot of the page.

Four alternatives to Postmark, compared row by row
CriterionRasketMailgunMailerSendBrevo
Sending and receiving
Inbound emailYes 1Receive at your own domain on every plan, delivered as a signed webhook.1 route on Free, 5 on Basic, full routing from Foundation 13Yes 20The plan table marks inbound routing on every plan, Free included.Yes 26Inbound parse webhooks, documented in their developer guide.
Transactional and campaigns on one planYes 2A campaign travels the same send pipeline as a password reset, on the same plan and the same key.Not published 13Not published 21Marketing campaigns and transactional email are both in the API 27
Idempotent sendsYes 4An Idempotency-Key is remembered for 24 hours.Not published 16Not published 23For batch transactional email 29An idempotencyKey, remembered for 30 minutes.
Versioned templatesYes 5Published versions with typed variables; every send records the version it used.Yes 17Up to 40 versions per template.Not published 23Not published 27
AutomationsYes 6Not published 13Not published 21Workflows, started by events their tracker records 30
SMTP relayYes 11smtp.rasket.com on 465 or 587, an API key as the password. Each message is an API send.Yes 13Yes 21Yes 35
DKIM key size2048-bit, one key per domain 12Not published 16Not published 23Not published 27
Webhooks and developer tools
Signed webhooksYes 3Yes 14A token, a timestamp and an HMAC-SHA256 signature posted with the event.Yes 22A Signature header holding an HMAC-SHA256 of the body, keyed by a per-webhook signing secret.No signature: IP allowlist, basic auth or a token 28Their secure-webhooks guide offers allowlisting Brevo's IP ranges, a username and password in the URL, a bearer token or custom headers; it describes no signature over the payload.
Replay a webhook eventYes 3Send the event again from the dashboard or the API; a replay carries the identical payload under the same event id.Not published 15Not published 22Not published 27
MCP serverYes 7An HTTP MCP server with seven toolsets, plus a setup skill.Yes 18Yes 24Yes 31
Markdown docs and llms.txtYes 8Markdown at every docs URL, with llms.txt and llms-full.txt.Yes 16A .md suffix on a documentation URL returns Markdown, and llms.txt maps the set.Yes 25A .md suffix on a developer documentation URL returns Markdown, and the developer site's llms.txt indexes it.Yes 27A .md suffix on a developer documentation URL returns Markdown, and llms.txt indexes them.
Official SDKsComing soon 9Coming soon: the rasket package is not published yet. Today, every language sends over the REST API.Ruby, PHP, Python, Java, Go and Node.js 19PHP, Laravel, Node.js, Go, Python, Ruby and Java 23Node.js, PHP, Python, Java, C#, Go and Ruby 32
Plans and pricing
Free plan3,000 emails a month, 100 emails a day, 3 domains 10100 emails a day 13500 emails a month, 1 domain, 1 template 20A card is asked for when you subscribe, though the plan is free.300 emails a day 33Sending opens once Brevo approves the account.
Entry paid plan$20 a month for 50,000 emails 10$15 a month for 10,000 emails 13The Basic plan.$7 a month for 5,000 emails 21The Hobby plan, paying monthly.$9 a month for 5,000 emails 34The Starter plan, paying monthly. Their pricing FAQ says every plan includes the transactional email features.
Extra emails, per 1,000$0.60 10The rate steps down to $0.25 as the Scale ladder climbs.From $1.80 on Basic 13From $1.30 on Foundation and from $1.10 on Scale.$0.90 on Starter and Professional 21That is the plan cards' rate; Hobby's card says $1.50. The same page's FAQ prices extra mail at $1.30 per 1,000 on the 100,000-email Starter tier, so the page gives two figures.No per-1,000 rate: email volume is bought in steps 34On Starter, 50,000 emails a month is the $9 plan plus a $47 step, by the Markdown price list on their site.
Data retention30 days on the self-serve plans 10Custom retention on a Custom plan.1 day of logs on Free and Basic, 5 on Foundation, 30 on Scale 131 day on Free and Hobby, 7 on Starter, 30 on Professional 20Unlimited log retention 33Their pricing FAQ lists it among the transactional email features every plan includes.
Dedicated IP$30 a month per address on Scale 10Recommended above 5,000 emails a day; the choice is the customer's.One included from Foundation 100k and on Scale, extra IPs $59 a month each 13Foundation 100k is $75 a month; the plan table says a dedicated IP can be added from the 50,000-email Foundation tier.For Enterprise accounts sending over 100,000 emails a week 21The plan table also lists a dedicated IP add-on on Professional; no price is stated.Listed on the Enterprise plan 33No price is published; Enterprise is sold through their sales team.
Best forProducts that send campaigns and receive replies as well as sending receiptsTeams who route inbound mail with rules and want a relay in front of itSmall projects that want the cheapest paid plan on this listTeams who want marketing, CRM and transactional email from one vendor

Moving your domain off Postmark

Add the domain in Rasket and publish the generated DKIM, SPF and DMARC records; verification runs on its own and you can keep sending through Postmark meanwhile. Then swap the call — POST /emails carries the same fields as their email endpoint, and a template alias becomes a Rasket template published as a version. Over SMTP, the server token you log in with becomes the username rasket and a Rasket key, and the host becomes smtp.rasket.com. Point your webhook handler at Rasket's signed events, verify the signature rather than the basic-auth credentials you were checking, and replay a delivery from the dashboard to test it.

Nothing about a verified sending domain is exclusive, so both providers can hold it while you move. Send a small share of your mail through the new one first, watch the delivery and bounce events, and cut the rest over once the numbers look like the old ones.

Frequently asked questions

What is the best Postmark alternative for developers?

We build Rasket, so read this as a disclosed preference and not a verdict. Yes, and the webhook row is the reason most teams look. Postmark's documentation states that they do not support HMAC signatures on webhooks; Rasket signs every event and you can replay one from the dashboard. Rasket also includes inbound mail on every plan and charges $0.60 per extra thousand against $1.80 on Basic. Postmark keeps history longer by default — 45 days against 30 — and publishes six client libraries where Rasket's are not out yet, so weigh those before moving.

Is there a free Postmark alternative?

Rasket: 3,000 emails a month, 100 emails a day, 3 domains. Mailgun: 100 emails a day. MailerSend: 500 emails a month, 1 domain, 1 template. Brevo: 300 emails a day. Each figure is from that vendor's own pricing page on 2026-10-17.

Which Postmark alternative includes inbound email?

Rasket: Yes. Mailgun: 1 route on Free, 5 on Basic, full routing from Foundation. MailerSend: Yes. Brevo: Yes. Inbound means receiving mail at your own domain, not just sending from it.

Which Postmark alternative works with AI agents?

Rasket: Yes. Mailgun: Yes. MailerSend: Yes. Brevo: Yes. An MCP server is what lets an assistant call the API directly; Markdown docs and llms.txt is the other half, and it reads: Rasket: Yes. Mailgun: Yes. MailerSend: Yes. Brevo: Yes.

How do I move my domain off Postmark?

Add the domain in Rasket and publish the generated DKIM, SPF and DMARC records; verification runs on its own and you can keep sending through Postmark meanwhile. Then swap the call — POST /emails carries the same fields as their email endpoint, and a template alias becomes a Rasket template published as a version. Over SMTP, the server token you log in with becomes the username rasket and a Rasket key, and the host becomes smtp.rasket.com. Point your webhook handler at Rasket's signed events, verify the signature rather than the basic-auth credentials you were checking, and replay a delivery from the dashboard to test it.

Sources

  1. 1Rasket — https://www.rasket.com/features/receiving. Read 2026-09-16.
  2. 2Rasket — https://www.rasket.com/features/broadcasts. Read 2026-10-17.
  3. 3Rasket — https://www.rasket.com/features/webhooks. Read 2026-10-17.
  4. 4Rasket — https://www.rasket.com/docs/idempotency. Read 2026-10-17.
  5. 5Rasket — https://www.rasket.com/features/templates. Read 2026-10-17.
  6. 6Rasket — https://www.rasket.com/features/automations. Read 2026-10-17.
  7. 7Rasket — https://www.rasket.com/features/agents. Read 2026-09-16.
  8. 8Rasket — https://www.rasket.com/llms.txt. Read 2026-09-16.
  9. 9Rasket — https://www.rasket.com/docs/quickstart. Read 2026-10-17.
  10. 10Rasket — https://www.rasket.com/pricing. Read 2026-10-17.
  11. 11Rasket — https://www.rasket.com/docs/smtp. Read 2026-09-29.
  12. 12Rasket — https://www.rasket.com/features/domains. Read 2026-10-17.
  13. 13Mailgun — https://www.mailgun.com/pricing/. Read 2026-10-17.
  14. 14Mailgun — https://documentation.mailgun.com/docs/mailgun/user-manual/webhooks/securing-webhooks. Read 2026-10-17.
  15. 15Mailgun — https://documentation.mailgun.com/docs/mailgun/user-manual/webhooks/webhooks. Read 2026-10-17.
  16. 16Mailgun — https://documentation.mailgun.com/llms.txt. Read 2026-10-17.
  17. 17Mailgun — https://documentation.mailgun.com/docs/mailgun/user-manual/sending-messages/send-templates. Read 2026-10-17.
  18. 18Mailgun — https://documentation.mailgun.com/docs/mailgun/mcp. Read 2026-10-17.
  19. 19Mailgun — https://documentation.mailgun.com/docs/mailgun/sdk/introduction. Read 2026-10-17.
  20. 20MailerSend — https://www.mailersend.com/pricing.md. Read 2026-10-17.
  21. 21MailerSend — https://www.mailersend.com/pricing. Read 2026-10-17.
  22. 22MailerSend — https://developers.mailersend.com/api/v1/account/webhooks. Read 2026-10-17.
  23. 23MailerSend — https://developers.mailersend.com/. Read 2026-10-17.
  24. 24MailerSend — https://developers.mailersend.com/mcp. Read 2026-10-17.
  25. 25MailerSend — https://developers.mailersend.com/llms.txt. Read 2026-10-17.
  26. 26Brevo — https://developers.brevo.com/docs/inbound-parse-webhooks. Read 2026-10-17.
  27. 27Brevo — https://developers.brevo.com/llms.txt. Read 2026-10-17.
  28. 28Brevo — https://developers.brevo.com/docs/secured-webhooks. Read 2026-10-17.
  29. 29Brevo — https://developers.brevo.com/docs/heterogenous-versions-batch-emails. Read 2026-10-17.
  30. 30Brevo — https://developers.brevo.com/guides/track-website-activity. Read 2026-10-17.
  31. 31Brevo — https://developers.brevo.com/docs/mcp-protocol. Read 2026-10-17.
  32. 32Brevo — https://developers.brevo.com/docs/api-clients. Read 2026-10-17.
  33. 33Brevo — https://www.brevo.com/pricing/. Read 2026-10-17.
  34. 34Brevo — https://www.brevo.com/pricing.md. Read 2026-10-17.
  35. 35Brevo — https://developers.brevo.com/docs/smtp-integration. Read 2026-10-17.

Last checked 2026-10-17. Prices and plan contents change. Every figure above was read from the linked page on the date beside it; if one has moved since, the page it came from is the one to trust.

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