Emailactive

Postmark API for coding agents

Postmark pairs mature transactional-email primitives with concrete agent instructions and a safe test token. It is a strong choice when delivery workflows matter more than a broad marketing suite.

#3of 7

Email API agent readiness

Completed a clean public setup run and publishes an official agent skill, build spec, test token, and mature SDKs.

Last checked Aug 17, 2026 4 primary sources Public setup result

Public evidence

1m 21s public setup run with 0 recorded errors.

Public setup benchmark measured an autonomous setup run using Claude Code · Opus 4.6.

First-party integration signals

Agent build specCopyable integration prompt

Agent skillOfficial Postmark skill

Test tokenValidates without delivery

Official SDKsSeven stacks

MCP serverNot found

OpenAPINot found

Public setup run

Claude Code · Opus 4.6

Setup run completed

Postmark completed the public setup run without a recorded error and required one human interruption.

Time: 1m 21s
Errors: 0
Interruptions: 1
Cost: $0.56

This setup result is separate from the All Them APIs task score.

View Agent Bench results

Agent verdict

Can a coding agent use Postmark? Yes.

Postmark now publishes an agent-ready build spec and an official skill alongside direct SDK installation. The test token makes payload validation unusually straightforward.

Agent guidance plus mature SDKs

Recommended setupOfficial Node.js SDK

Coding agent skill

npx skills add ActiveCampaign/postmark-skills

Installs Postmark's published integration guidance for compatible coding agents.

Node.js / TypeScript

npm install postmark

Set POSTMARK_SERVER_TOKEN in the server environment and use the official ServerClient.

Open official setup documentation

Supported workflows

Common Postmark workflows

Send transactional email

Send template-based messages

Process inbound email

Track delivery with webhooks

Decision guide

Is Postmark a fit?

Good fit

Operational and transactional email
Teams that separate email by application or stream
Agents that benefit from a copyable build spec

Check before shipping

A sender signature or domain must be confirmed
No first-party MCP server found
Different token types apply to server and account operations

Reference

API limits and source records

Base URL, authentication, pricing, SDKs, rate limits, and checked documentation.

API basics

Base URL: https://api.postmarkapp.com
Authentication: Server token and Account token
Free tier: Developer plan and test token available; see current pricing
Rate limit: Endpoint dependent; batch and recipient limits are documented per operation
Testing: POSTMARK_API_TEST validates send payloads without delivering email

7 official SDKs

Node.js / TypeScript Python Ruby PHP .NET Java Rails

4 checked sources

API overviewbase URL · token types · REST Get startedagent skill · build spec · SDK installation Send with APIsend endpoint · test token · sender requirements Official librariesofficial SDKs

Pricing, status, and alternatives

Pricing Status Changelog GitHubResendMailgunLoops

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