Postfix

aid: postfix
name: Postfix
description: Postfix is a free, open source mail transfer agent (MTA) originally written by Wietse Venema at IBM Research
  as a fast, secure, and easy-to-administer alternative to Sendmail. It runs on UNIX-like systems including Linux, BSD, and
  macOS, routing and delivering email over SMTP with extensive support for TLS, SASL, DKIM/SPF/DMARC integration, content
  filtering, and policy delegation. Postfix is administered via configuration files (main.cf, master.cf) and command-line
  tools rather than a public HTTP API, and is one of the most widely deployed mail servers on the internet.
type: Index
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
tags:
- Email
- Mail Server
- MTA
- SMTP
- Open Source
- Infrastructure
url: https://raw.githubusercontent.com/api-evangelist/postfix/refs/heads/main/apis.yml
created: '2026-05-11'
modified: '2026-05-11'
specificationVersion: '0.19'
apis:
- aid: postfix:smtp
  name: Postfix SMTP
  description: 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.
  humanURL: https://www.postfix.org/documentation.html
  baseURL: smtp://localhost:25
  tags:
  - SMTP
  - Email
  - Mail Server
  - Protocol
  properties:
  - type: Documentation
    url: https://www.postfix.org/documentation.html
  - type: SMTP Specification
    url: https://datatracker.ietf.org/doc/html/rfc5321
  - type: Configuration Reference
    url: https://www.postfix.org/postconf.5.html
  - type: Milter Protocol
    url: https://www.postfix.org/MILTER_README.html
common:
- type: VulnerabilityDisclosure
  url: security/postfix-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/postfix-domain-security.yml
- type: Website
  url: https://www.postfix.org
- type: Documentation
  url: https://www.postfix.org/documentation.html
- type: Download
  url: https://www.postfix.org/download.html
- type: Source Code
  url: https://github.com/vdukhovni/postfix
- type: Mailing Lists
  url: https://www.postfix.org/lists.html
- type: Security
  url: https://www.postfix.org/security.html
- type: License
  url: https://www.postfix.org/license.html
- type: Wikipedia
  url: https://en.wikipedia.org/wiki/Postfix_(software)
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com