Postmark review: transactional email API with strong deliverability. Compare features, pricing plans, and alternatives like SendGrid and Amazon SES.
Category
Email Marketing
Pricing
Freemium, from Free (100 emails/month); paid plans start at $15/month
Verified
Not yet
Last updated
July 19, 2026
Founded
2009
Headquarters
Chicago, Illinois, United States (ActiveCampaign HQ; Postmark originated in Philadelphia, Pennsylvania as a Wildbit product)
Free PlanWeb AppAPI
Overview
Postmark is a transactional email API and delivery service that developers integrate into applications to send system-triggered messages like password resets, receipts, shipping notifications, and account alerts.
Its defining principle since launch has been keeping transactional email fully separate from marketing email traffic, which the company argues protects sending reputation and keeps deliverability rates high for time-sensitive messages.
Key Features
Postmark provides SMTP and REST API access with official libraries for languages including Ruby, PHP, Python, Node.js, and .NET, along with inbound email parsing that can turn incoming replies into structured webhook data for an application.
The platform includes a searchable message activity log, delivery and bounce tracking, open and click analytics, spam complaint monitoring, and support for multiple custom sending domains with DKIM and DMARC configuration.
Pricing
Postmark uses a usage-based freemium model. The Free plan allows up to 100 emails per month at no cost, aimed at testing and evaluating deliverability during development.
Paid plans -- Basic, Pro, and Platform -- all include a base of 10,000 emails per month starting between roughly $15 and $18/month, with the higher tiers offering longer message retention (up to 365 days), more or unlimited custom sending domains, and inbound processing; large-volume senders can request custom Enterprise pricing.
Key Features
Transactional-only sending — Keeps app-triggered emails separate from marketing sends to protect deliverability and sender reputation.
SMTP and REST API — Integrate email sending via SMTP or a REST API, with official libraries for major languages and frameworks.
Message activity log — Search and inspect the full history of every email sent, including delivery status, opens, and clicks.
Inbound email processing — Parse incoming email replies into structured data delivered to your application via webhook.
Deliverability tooling — Monitor bounce rates, spam complaints, and sender reputation, with DKIM, SPF, and DMARC support for custom domains.
Templates — Build and manage reusable email templates with layout and variable support for transactional messages.
Detailed analytics — Track opens, clicks, and delivery performance per message and per sending domain.
Pros & Cons
Pros
Strong, long-standing reputation for transactional email deliverability
Clear, transparent usage-based pricing that scales with email volume
Developer-friendly API, SMTP support, and official libraries for major languages
Detailed per-message activity log and analytics
Now backed by ActiveCampaign's resources while still operating as a focused, standalone product
Cons
Free plan is limited to 100 emails per month, quite small for active testing
Strictly transactional focus means it's not a fit for teams wanting marketing email in the same tool
Per-email costs can add up for very high-volume senders compared to some bulk-oriented providers
Fewer built-in marketing-automation features than all-in-one platforms
Some users report a learning curve configuring custom domain authentication for optimal deliverability
Pricing
Free $0/month monthly
Basic $15/month monthly
Pro $16.50/month monthly
Platform $18/month monthly
Enterprise Custom (contact sales) custom
Frequently Asked Questions
What is Postmark used for?
Postmark is used to send transactional, application-triggered emails such as password resets, receipts, and account notifications, not marketing campaigns.
Is Postmark free?
Postmark offers a free plan covering up to 100 emails per month; paid plans start around $15/month for 10,000 emails.
Who owns Postmark?
Postmark was created by Wildbit and acquired by ActiveCampaign in May 2022, where it continues to operate as a standalone product.
Does Postmark support marketing email?
No, Postmark is intentionally built for transactional email only and does not support bulk marketing sends on the same infrastructure.
Does Postmark have an API?
Yes, Postmark offers both SMTP and REST API access along with official libraries for languages like Ruby, PHP, Python, Node.js, and .NET.
What are Postmark's main competitors?
Common alternatives include SendGrid, Amazon SES, Mailgun, and Resend.
Can Postmark process incoming email?
Yes, its inbound email processing feature parses incoming messages and delivers them to your application as structured webhook data.
How long does Postmark retain message data?
Data retention depends on plan, ranging from 45 days on the Basic plan up to 365 days on Pro and Platform plans.