Postal

API

Self-hosted open-source mail server with an HTTP API and SMTP

Price: Free, open source
Access: Server API key

About

Postal is an open-source mail delivery platform you run on your own servers. It sends and receives email through SMTP or an HTTP API, with a web interface for servers and logs, webhooks for delivery events and IP pools.

What you can do with it

Send transactional email from your own mail server over HTTP or SMTP
Receive delivery events as webhooks and review message logs
Run an open-source alternative to hosted email APIs on your own servers

Get started

Install Postal on your own server
Create an API credential in the web interface

Example

curl -X POST https://postal.example.com/api/v1/send/message \
  -H "X-Server-API-Key: $POSTAL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"to":["recipient@example.com"],"from":"sender@example.com","subject":"hello","plain_body":"it works"}'

Details

Hosting: Self-hosted
Available in: Worldwide
Official SDKs: PHP
MCP server: None