# Postmark — API Agent Score

> Score: 62/100 (Grade: C) | Domain: postmarkapp.com | Rubric: 1.0.0 | Checked: July 24, 2026

Postmark scored 62/100 (C), classified "partially-ready".

[View full report](https://www.postman.com/ai/ai-ready-apis/company/postmarkapp)
[All organizations](https://www.postman.com/ai/ai-ready-apis/llms.txt)

## Summary

- Overall: 62/100 (C)
- Classification: partially-ready

## Category Scores

- API Design: 60/100 (C)
- Developer Experience: 71/100 (B)
- Agent Discovery: 79/100 (B)
- Agent Understanding: 79/100 (B)
- Agent Usability: 40/100 (F)

## Check Results

### API Design

- [warn] Machine-readable, versioned contract — info.version="1.0.0" set but no versioning scheme (URL / header / media type) detected. Investigated: spec 75%, docs 50%.
- [pass] Security & governance hygiene — No credential-shaped strings detected in spec. Investigated: spec 100%, wellknown 0%.
- [warn] Schema coverage & depth — Only 70% of operations have documented schemas. Investigated: spec 58%.
- [fail] Auth declared & discoverable — No securitySchemes declared. Investigated: spec 0%, docs 0%.
- [fail] Example coverage — 0% example coverage. Investigated: spec 0%.

### Developer Experience

- [pass] Quickstart present — Quickstart at https://postmarkapp.com/developer/get-started with a runnable first-call sample. Investigated: docs 100%.
- [pass] Description completeness — 71% description completeness (target 90%+). Investigated: spec 100%.
- [pass] Changelog published — Newest official SDK activity 3 day(s) ago. Investigated: sdk 100%, spec 0%, docs 0%.
- [fail] Self-service developer portal — No signup page detected across conventional paths (/signup, /sign-up, /register, /get-started, /console/signup, /dashboard/signup, /try, /try-free, /free, /free-trial, /start, /start-free). Investigated: docs 0%.
- [skip] Code samples in docs — No surface produced evidence for this capability in this run.

### Agent Discovery

- [pass] Registry & SDK presence — Indexed on Context7 (websites/postmarkapp_developer, 1085 snippets). Investigated: docs 100%, sdk 100%, cli 0%.
- [warn] Docs reachable, not hard auth-gated — Server ignores Accept: text/markdown header (0/50 sampled pages return markdown); 40 rate-limited (HTTP 429). Investigated: docs 75%.
- [warn] llms.txt present, valid & comprehensive — llms.txt covers 17/51 sitemap doc pages (33%); 34 missing. Investigated: docs 44%.
- [pass] Crawlable / AEO — Docs paths crawlable by all monitored AI agents. Investigated: wellknown 100%.

### Agent Understanding

- [pass] Machine-readable errors (RFC 9457) — Only 2 distinct 4xx/5xx codes documented (plus 0 "default" catch-all responses). Investigated: spec 100%, docs 100%.
- [pass] Operation purpose clarity — 95% of operations have a clear summary + operationId an agent can select on. Investigated: spec 100%.
- [warn] Agent-navigable, token-efficient docs — No sampled pages support .md URLs (0/50 tested). Investigated: docs 50%.
- [fail] Agent instructions file (AGENTS.md) — No AGENTS.md at the site root or /.well-known/. Investigated: wellknown 0%.
- [skip] Docs structured data — No surface produced evidence for this capability in this run.
- [skip] Description consistency across surfaces — Only 1 surface description(s) with ≥6 tokens available; need at least 2 to compare.

### Agent Usability

- [fail] Idempotency documented — 0% of mutating operations document idempotency. Investigated: spec 0%, docs 0%.
- [fail] Rate-limit signaling — No rate-limit response headers documented. Investigated: spec 0%, docs 0%.
- [fail] Sandbox separation — No sandbox/test server declared across 1 server entries; no test-key prefixes documented. Investigated: spec 0%, docs 0%.
- [fail] Runnable collection with test scripts — No public Postman workspace discovered for the org. Investigated: platform 0%.
- [skip] Pagination documented & consistent — No surface produced evidence for this capability in this run.

## Executive Summary

Postmarkapp's API program shows real strengths in documentation reachability and schema clarity, but partners and their agents face three compounding blockers today: the API cannot be safely or reliably automated (missing sandbox, idempotency guidance, and rate-limit signaling), runnable examples are absent so agents must guess at request shapes, and there is no machine-readable instruction layer to help AI agents understand how to work with the API. Fixing agent usability and runnable truth first will have the most immediate impact on partner integration success, followed by closing the auth discoverability and example coverage gaps that slow both human and agent onboarding.