# Fly — API Agent Score

> Score: 74/100 (Grade: B) | Domain: fly.io | Rubric: 1.0.0 | Checked: July 24, 2026

Fly scored 74/100 (B), classified "partially-ready".

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

## Summary

- Overall: 74/100 (B)
- Classification: partially-ready

## Category Scores

- API Design: 75/100 (B)
- Developer Experience: 89/100 (A)
- Agent Discovery: 79/100 (B)
- Agent Understanding: 78/100 (B)
- Agent Usability: 56/100 (D)

## Check Results

### API Design

- [pass] Machine-readable, versioned contract — Versioning declared (info.version="1.0") and url-versioning detected. Investigated: spec 100%, docs 100%.
- [warn] Schema coverage & depth — 1 of 5 public signatures use loose types (anyTypeRatio=0.200). Investigated: sdk 80%, spec 67%.
- [pass] Security & governance hygiene — No credential-shaped strings detected in spec. Investigated: spec 100%, wellknown 0%.
- [pass] Example coverage — Code samples present on 2/20 pages across 2 language(s); broader multi-language coverage missing. Investigated: docs 100%, sdk 100%, spec 0%.
- [fail] Auth declared & discoverable — No securitySchemes declared. Investigated: spec 0%, docs 0%.

### Developer Experience

- [pass] Self-service developer portal — Self-service signup at https://fly.io/app/sign-in?return_to=%2Fdashboard%2Fsignup; free tier / sandbox documented. Investigated: docs 100%.
- [pass] Code samples in docs — Code samples present on 2/20 pages across 2 language(s); broader multi-language coverage missing. Investigated: docs 100%.
- [pass] Description completeness — 84% description completeness (target 90%+). Investigated: spec 100%, sdk 0%.
- [pass] Changelog published — changelog documented in the docs site at https://fly-changelog.fly.dev/. Investigated: spec 100%, docs 100%, sdk 100%.
- [warn] Quickstart present — Quickstart page reachable (1 variants scanned starting at https://fly.io/docs/getting-started/) but no runnable code sample detected in HTML or .md variant. Investigated: docs 50%.

### Agent Discovery

- [pass] Registry & SDK presence — Indexed on Context7 (websites/fly_io, 13082 snippets). Investigated: docs 100%, sdk 75%, cli 50%.
- [warn] Docs reachable, not hard auth-gated — Server ignores Accept: text/markdown header (0/50 sampled pages return markdown). Investigated: docs 75%.
- [warn] llms.txt present, valid & comprehensive — No llms.txt directive found in HTML of any of 50 sampled pages. Investigated: docs 50%, sdk 0%.
- [warn] Crawlable / AEO — Sitemap present (2 entries) but carries no lastmod values. Investigated: wellknown 75%.

### Agent Understanding

- [pass] Machine-readable errors (RFC 9457) — 6 distinct 4xx/5xx response codes documented. Investigated: docs 100%, spec 50%.
- [pass] Operation purpose clarity — 96% 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 69%.
- [warn] Docs structured data — JSON-LD on 1/4 assessed pages, but coverage is sparse or dateModified is missing. Investigated: docs 50%.
- [warn] Description consistency across surfaces — Mean pairwise description similarity across 2 surfaces (spec, docs) is 10% (threshold 35% for full credit).
- [fail] Agent instructions file (AGENTS.md) — No AGENTS.md at the site root or /.well-known/. Investigated: wellknown 0%.

### Agent Usability

- [pass] Pagination documented & consistent — Pagination params detected on 6 list endpoint(s). Investigated: docs 100%, spec 75%.
- [pass] Sandbox separation — sandbox documented in the docs site at https://fly.io/learn/virtual-sandbox/. Investigated: spec 100%, docs 100%, sdk 50%.
- [fail] Idempotency documented — 0% of mutating operations document idempotency. Investigated: spec 0%, docs 0%, sdk 0%.
- [fail] Rate-limit signaling — No rate-limit response headers documented. Investigated: spec 0%, docs 0%.
- [fail] Runnable collection with test scripts — No public Postman workspace discovered for the org. Investigated: platform 0%.

## Executive Summary

Fly.io's developer experience is a genuine strength — partners can get started quickly and the API surface is largely well-designed. The two areas that need urgent attention are agent usability and agent understanding: partners' AI agents lack the runnable, executable context they need to integrate correctly, and there is no structured instruction file or idempotency/rate-limit guidance to help agents navigate the API reliably. Fixing these gaps will protect partner integrations from hallucination, silent failure, and unnecessary support escalation, and will make Fly.io's APIs a first-class target for AI-assisted development workflows.