Postmark

Transactional email API and SMTP service built for deliverability

A transactional email API and SMTP service focused on deliverability and speed, with separate message streams for transactional and broadcast email, inbound email processing and 45 days of message history by default.

// quick verdict

Postmark is a deliverability-first email API for app-generated email, with separate streams for transactional and broadcast mail and unusually long default message history. Pick Basic if you just need reliable sending from a few domains; step up to Pro once you need inbound email, more domains or longer retention.

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// best for

Solo developers and small SaaS teams who send password resets, receipts and notifications from their own app and want predictable deliverability, clear message history for debugging, and a free plan for building the integration.

// not ideal for

Very low-volume senders who need something between 100 and 10,000 emails a month, teams that only send newsletters (a newsletter platform such as Beehiiv fits better), or buyers who need annual billing or PayPal.

Pros

+The free developer plan includes 100 emails a month with no expiry, enough to build and test an integration before paying
+Transactional and broadcast email run on separate Message Streams, so marketing sends do not drag down the reputation of password resets and receipts
+Every plan keeps 45 days of full message content and activity for troubleshooting, with custom retention up to 365 days on Pro and above
+Postmark publishes its delivery statistics to major inbox providers on its public status page

Cons

−There is no tier between the 100-email free plan and the 10,000-email paid plans, and unused emails do not roll over
−Inbound email processing and custom retention start at Pro, not Basic
−No annual billing option yet, and payment is by card only (no PayPal or purchase orders)
−Dedicated IPs are only offered to senders on Pro or higher who send 300,000+ emails per month

Pricing

last scrape: Oct 15, 2026source ↗

Free

$0free forever

›Testing your integration
›Evaluating Postmark's deliverability
›Side projects with low volume

Basic

$15/mo

›Industry-leading deliverability rates & speed
›45-day data retention
›5 Custom sending domains
›Unlimited emails/day
›Detailed analytics and insights

Pro

$16.50/mo

›Industry-leading deliverability rates & speed
›Customizable data retention up to 365 days (45-day default)
›10 Custom sending domains
›Unlimited emails/day
›Detailed analytics and insights

Platform

$18/mo

›Industry-leading deliverability rates & speed
›Customizable data retention up to 365 days (45-day default)
›Unlimited Custom sending domains
›Unlimited emails/day
›Detailed analytics and insights

Price history

last 180 daysfull change log →

pro

platform

basic

Hands-on notes

last reviewed: Oct 10, 2026

Postmark is an email delivery service for developers: your application sends email through its REST API or SMTP, and Postmark handles authentication, delivery, bounces and tracking. It was built for transactional email — password resets, receipts, notifications — and still positions deliverability and delivery speed as its main selling points, publishing its delivery statistics on a public status page.

A feature worth understanding before you compare providers is Message Streams. Transactional and broadcast (bulk) email are sent through separate infrastructure within the same account, so a marketing send does not affect the reputation of your critical app email. Postmark also offers a Bulk Email API for broadcasts, responsive templates with an editor and import tool, event webhooks and official SDKs.

Pricing is volume-based. Every account starts on the free developer plan, which includes 100 emails a month and does not expire. Paid plans start at 10,000 emails a month, with extra emails billed per thousand at the end of the billing cycle; the per-thousand rate falls as you move up from Basic to Pro to Platform. The three paid plans differ mainly in limits rather than core sending: Basic covers up to 5 sending domains and 4 users, Pro raises that to 10 domains and adds inbound email processing and customizable retention, and Platform removes the domain, server and user limits for agencies and larger teams.

There are a few gaps to be aware of. Postmark has no tier between 100 and 10,000 emails a month, unused emails do not roll over, and there is no annual plan yet. Bootstrapped companies that have launched and are charging customers can ask support for an account credit. High-volume senders can talk to sales about custom pricing and dedicated IPs.

This review is documentation-based, sourced from Postmark’s public pricing page, feature comparison and FAQ. Live pricing on the right-hand card is updated by our scraper.

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