# Postfix SMTP

**Canonical:** https://apis.io/apis/postfix/smtp/  
**Provider:** Postfix — https://apis.io/providers/postfix/  
**Base URL:** smtp://localhost:25  
**Documentation:** https://www.postfix.org/documentation.html

Postfix SMTP is published by [Postfix](https://apis.io/providers/postfix/) on the [APIs.io](https://apis.io/) network. Tagged areas include SMTP, Email, Mail Server, and Protocol. The published artifact set on APIs.io includes API documentation.

Postfix implements SMTP (RFC 5321) for sending and receiving electronic mail, with submission (port 587), SMTPS (port 465), and standard SMTP (port 25) endpoints. There is no public HTTP/REST API; integration is via SMTP protocol, configuration files, milter (mail filter) hooks, and policy daemons.

## Machine-readable artifacts (5)

- **Documentation** — https://www.postfix.org/documentation.html
- **SMTP Specification** — https://datatracker.ietf.org/doc/html/rfc5321
- **Configuration Reference** — https://www.postfix.org/postconf.5.html
- **Milter Protocol** — https://www.postfix.org/MILTER_README.html
- **APIsJSON** — https://raw.githubusercontent.com/api-evangelist/postfix/refs/heads/main/apis.yml

## Tags

SMTP, Email, Mail Server, Protocol

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/postfix/smtp/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/postfix/.