# Postfix

**Canonical:** https://apis.io/providers/postfix/  
**Website:** https://www.postfix.org  
**APIs profiled:** 1

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.

## Kin Score — 9.9 / 100 (minimal)

Scored 2026-08-25 under rubric 0.14.0. Trend: flat (+0.0 from 9.9).

| Facet | Score |
|---|---|
| Discoverability | 59.3 |
| Contract Quality | 0.0 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 15.8 |
| Developer Ergonomics | 9.5 |
| Commercial Clarity | 0.0 |
| Access Clarity | 0.0 |

## Agent readiness — 0.0 (human-only)

| Dimension | Value |
|---|---|
| Spec Presence | no |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |
| Delegated Identity | no |
| Protected Resource Metadata | no |
| Dynamic Client Registration | no |
| Agentic Commerce | no |

## Access

Unknown — onboarding: unknown, pricing: unknown, trial: no (confidence: low).

## APIs (1)

- **Postfix SMTP** — 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 pu...

## Security (2)

- **Postfix Domain Security** — TLSv1.3 · DNSSEC
- **Postfix Vulnerability Disclosure** — security.txt · contact published

## Tags

Email, Mail Server, MTA, SMTP, Open-Source, Infrastructure

---

Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/postfix/). Scores are computed from the provider's own public artifacts under a published rubric.