Postmark features: what you get on each plan

Feature matrix

Feature by feature

Postmark webhooks

Webhooks are on the free tier, with seven event types: delivery, bounce, spam complaint, open tracking, click, subscription change and inbound. Only the last carries a plan condition, because inbound itself needs Pro. The rest fire from the first free send.

The retry policy is where the detail matters. Postmark retries on 5xx, 408, 429 and network failures, never on a 4xx. The schedule is six attempts spaced 1, 5, 10, 10, 10 and 15 minutes apart, so the whole retry window closes in about fifty minutes. An endpoint down for a two hour maintenance slot does not get its events replayed afterwards — it loses them. If your consumer cannot promise better than an hour of uptime, put a queue in front of it.

Security is the other place to read carefully. You can pin Postmark’s published IP ranges, put basic auth credentials in the webhook URL and insist on HTTPS. What you cannot do is verify a signature: the documentation states plainly that Postmark does not currently support HMAC webhook signature verification. Your endpoint therefore authenticates the sender by source address or by a secret sitting in a URL, both of which are weaker than a signed body, and both of which leak into logs more easily than a header does. Treat the payload as unauthenticated input and re-fetch anything consequential through the API.

Postmark templates

Templates are free, stored server side, and capped at 100 templates per server. Two kinds exist: standard templates carrying a subject, an HTML body and a text body, and layout templates that wrap a standard template through a content placeholder, so a shared header and footer live in one place.

The templating language is the reason to care. Alongside plain substitution such as {{name}} and dotted paths such as {{company.name}}, it supports conditional blocks and iteration — {{#each person}} walks a list. That sounds unremarkable until you compare it with the stored templates of other transactional providers, several of which offer substitution and nothing else. An order confirmation with a variable number of line items, an invoice with a variable number of rows, a digest with a variable number of items: all of these stay inside a stored Postmark template instead of being rendered in your application and pushed as raw HTML.

The workflow around them is unusually grown up too. Templates can be pushed from one server to another, and the push accepts a dry run flag so you can see what would change before it changes — a staging server and a production server holding the same set, with a reviewable promotion between them.

Two limits to plan around. The hundred is per server, not per account, so a multi tenant setup that gives each customer a server multiplies templates fast but also multiplies the ceiling. And there is no A/B testing anywhere in the product, so comparing two versions means splitting traffic yourself and reading the difference from the Stats API.

Plan gating notes

The free tier is a real tier. It carries ten servers, ten sending domains and six users — more of each than Basic, which drops to five, five and four. Basic buys two factor authentication, API permission controls, batch sending and broadcast streams; it does not buy headroom. Read the free column as a feature tier, not a trial.

The pricing grid contradicts itself on batch sending. Bulk Email API is checked on all four plans while batch sending is dashed on Free. The API reference gates neither, and states a ceiling of 500 messages per batched request with a 50 MB payload. We kept the grid’s stricter reading in the matrix and flag it here rather than pick a side.

Retention is bounded and the extension is gated. Paid plans keep detailed activity for 45 days. Longer windows exist only as an add-on from $5/month, and only on Pro or higher, so an investigation reaching back a quarter is a decision made in advance, not a support request made after the fact. Dedicated IPs are gated the same way: Pro or higher, from $50/month per IP, with a sending floor of 300,000 messages a month before Postmark will warm one.

Continue reading

• Postmark pricing — what each tier costs at your volume
• Postmark review — the verdict, and who it suits
• Postmark API — endpoints, tokens and limits
• Postmark alternatives — where to look next