Send email

Postmark

Email delivery service with REST API, SMTP, webhooks and inbound parsing for transactional and broadcast email.

Addresses

REST API: https://api.postmarkapp.com4
MCP server: No remote address; local stdio server via npx -y @activecampaign/postmark-mcp11
OpenAPI spec: https://postmarkapp.com/swagger/server.yml (account API: https://postmarkapp.com/swagger/account.yml)15
Docs for agents: https://postmarkapp.com/llms.txt; agent auth notes at https://postmarkapp.com/auth.md3
Status page: https://status.postmarkapp.com/15

Install

Rows come from the official libraries page (SDKs), the MCP server README and the postmark-cli README; the quote is the Python row.

What	Command
Official MCP server (Claude Desktop, Cursor and other clients, via JSON config)	`npx -y @activecampaign/postmark-mcp` with `POSTMARK_SERVER_TOKEN`, `DEFAULT_SENDER_EMAIL`, `DEFAULT_MESSAGE_STREAM` set
Node.js SDK	`npm install postmark`
Python SDK	`pip install postmark-python`
PHP SDK	`composer require wildbit/postmark-php`
CLI	`npm i postmark-cli -g`

Source10Official libraries

Install sources

Node.js SDK: npm install postmark13
CLI: npm i postmark-cli -g14
MCP required variables: POSTMARK_SERVER_TOKEN, DEFAULT_SENDER_EMAIL, DEFAULT_MESSAGE_STREAM11

Read from ActiveCampaign’s own pages on 2026-11-04. Every number links to the page a value came from. For agents, the same facts as markdown: /tools/send-email/postmark.md