Postmark

Overview

Postmark is a transactional email service that has been delivering mail for application developers since 2010, built around Message Streams: promotional and transactional mail run on parallel but completely separate sending infrastructures, so a promotional send cannot drag down the deliverability of a password reset. Mail goes out over a REST API authenticated with server and account tokens, or over an SMTP service with IP allowlisting, and comes back in through inbound processing that hands received messages to your application. Reusable templates with variable substitution are managed in the dashboard or through the Templates API, delivery events reach your systems through webhooks, and further endpoints cover bounce management and suppressions. Official client libraries span TypeScript, Node.js, Python, Ruby, Rails, PHP, .NET and Java, with a WordPress plugin, while community-maintained libraries add Go, Elixir, Laravel and Scala. Pricing is banded by monthly volume from a standing free tier of 100 emails, and the three paid plans all begin at the same 10,000 emails, differing in overage rate, inbound email and how far message data retention can be extended. Dedicated IPs, extended retention and DMARC monitoring are sold as add-ons on top.

Best for product and engineering teams whose transactional email has to arrive, and who want promotional sending kept on separate infrastructure.

Postmark fits teams for whom email is the part of the product that must not fail, and the price of that focus is everything it deliberately leaves out: a marketing team expecting to build a campaign unaided will not find the tooling here. Read the plan ladder as three overage rates rather than three feature sets, because the monthly figures all start at the same volume and the difference only shows up once you exceed it, so at steady high volume the cheaper headline plan can be the more expensive one. The free tier permits no overage at all, which makes it a genuine sandbox but not somewhere a live product can quietly sit. Postmark has been part of ActiveCampaign since April 2022 while continuing to run on its own sending infrastructure and IPs, so if long-term independence matters to your architecture, confirm the roadmap with the vendor rather than assuming it.

Key Facts

Features

Campaign types

Transactional and broadcast email on separate Message Streams, plus inbound email processing that delivers received mail to your application

Automation and journeys

No journey or automation builder. Sends are triggered by your own application over the API or SMTP, and delivery events are pushed back out through webhooks.

Segmentation and personalisation

No stored audiences or segment builder. Recipients and their personalisation values are supplied per request, while Postmark maintains bounce state and suppression lists.

Templates and editor

Reusable email templates with variable substitution, managed in the dashboard or over the Templates API; there is no drag-and-drop campaign designer

Deliverability and testing

Message Streams keep promotional sending on infrastructure separate from transactional mail. Message data is retained for 45 days, extendable to 365 days on Pro and Platform from $5 per month. Dedicated IPs start at $50 per month per IP and DMARC monitoring at $14 per month per domain.

Ecommerce and CRM data

No built-in ecommerce or CRM data sync. Contact data stays in your own application, which supplies it with each send.

Integrations and API

Yes, REST API with separate server and account tokens over TLS, plus an SMTP service with IP allowlisting. Endpoints cover email, batch sending, templates, bounces, inbound, message streams and suppressions. Official libraries for TypeScript, Node.js, Python, Ruby, Rails, PHP, .NET and Java, plus a WordPress plugin; community libraries add Go, Elixir, Laravel and Scala.

Integrations

Integrations coming soon.

Deployment and Support

Deployment

• Cloud (SaaS)
• Browser-based

Support

• Email helpdesk

Onboarding

• Documentation and knowledge base

Company size

• Freelancers
• Small and mid-sized
• Enterprise

Suitability

The table combines the industries the vendor addresses with the company sizes the tool is aimed at. An empty cell means the combination is not stated, not that it is ruled out.

Pros and Cons

Pricing

• Free

  $0

  100 emails per month with no overages permitted, and 45 days of data retention. Never expires.

• Basic

  $15

  Per month from 10,000 emails, overage $1.80 per 1,000. 45 days of data retention, no inbound email.

• Pro

  $16.50

  Per month from 10,000 emails, overage $1.30 per 1,000. Adds inbound email and data retention customisable to 365 days.

• Platform

  $18

  Per month from 10,000 emails, overage $1.20 per 1,000. Adds unlimited custom domains and message streams.

Best For

• Technology

Alternatives and Comparisons

FAQ

What are Postmark's Message Streams?

They are parallel but completely separate sending infrastructures for different kinds of mail. Promotional messages travel on one stream and transactional messages such as password resets and notifications on another, so a problem with promotional sending does not affect the deliverability of the mail your application depends on.

Does Postmark have a free plan?

Yes. The free tier covers 100 emails per month with 45 days of data retention and never expires. No overage is permitted on it, so sending stops once the 100 messages are used rather than continuing at a per-message rate.

What is the difference between the Basic, Pro and Platform plans?

All three start at 10,000 emails per month. Basic costs $15 with overage at $1.80 per 1,000, Pro $16.50 with overage at $1.30, and Platform $18 with overage at $1.20. Pro and Platform add inbound email processing and let data retention be extended to 365 days, and Platform adds unlimited custom domains and message streams.

Can Postmark send marketing campaigns?

It can send promotional mail on a broadcast Message Stream, but it is not a campaign tool. There is no journey builder, no stored audience and no drag-and-drop campaign designer, so recipients and their personalisation values are supplied by your own application with each send.

Who owns Postmark?

ActiveCampaign, which acquired Postmark and DMARC Digests from Wildbit in April 2022. Both remain available as standalone products, and Postmark's sending IPs, mail servers and Message Stream routing were kept separate from ActiveCampaign's own infrastructure.

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