APIs.io is a federated, agent-friendly directory of public-internet APIs. It indexes API providers from across the web — their APIs, JSON Schemas, event-driven specifications, governance rules, vocabularies, JSON-LD contexts, pricing plans, rate limits, FinOps profiles, the agent surfaces they publish (Agent Skills and MCP servers), and the industries and regions they serve — and publishes every slice of metadata as its own browsable section of the site.
The whole network is served from a single origin — one S3 + CloudFront distribution on the apex domain apis.io. Each catalog renders into its own path namespace (apis.io/providers/, apis.io/schemas/, …), and a read-only search API and an MCP server are served as paths under the same origin. The legacy per-subdomain sites (providers.apis.io, schemas.apis.io, …) now 301-redirect to their apex paths and are kept only as aliases. Every section carries the same agent-readiness baseline (llms.txt, RFC 9727 api-catalog, permissive robots.txt, schema.org JSON-LD).
The network is consumed via apis.io, the search API and MCP server, the RFC 9727
api-cataloglinkset, thellms.txt/llms-full.txtagent feeds, and the sitemaps. Everything below is open-access content, free to search, ground LLMs against, train on, or republish — see https://apis.io/terms/ for the full terms.
| Section | What you'll find |
|---|---|
| apis.io | Search hub for the whole network — search by provider, schema, tag, or name; blog; cross-network insights |
| apis.io/tags/ | Tag index across the network — every provider and API that carries a tag, scored and ranked |
| apis.io/industries/ | 29 industry verticals (Financial Services, Healthcare, Manufacturing, Transportation, Energy, Government, …) |
| apis.io/regions/ | 17 macro sales regions (North America, LATAM, EMEA, APAC, Greater China, ANZ, …) |
| apis.io/developer | Developer portal & machine-readable feeds |
| Section | What you'll find |
|---|---|
| apis.io/providers/ | API provider profiles — one page per organization, with cross-links to every artifact that organization publishes |
| apis.io/apis/ | Individual API records — one page per published API, with the OpenAPI spec and provider link |
| apis.io/schemas/ | JSON Schemas extracted from every indexed API — Google Dataset Search ingestion-ready |
| apis.io/collections/ | Postman Collections and Open Collections — ready-to-run request sets for thousands of APIs |
| apis.io/asyncapis/ | AsyncAPI event-driven specifications |
| apis.io/graphqls/ | GraphQL API specifications — endpoint URLs, documentation, and reference links |
| apis.io/channels/ | Event channels drilled out of every AsyncAPI spec — one page per channel |
| apis.io/arazzos/ | Arazzo API workflow specs — provider-specific and cross-provider multi-step workflows |
| apis.io/jsonld/ | JSON-LD contexts and semantic vocabularies |
| apis.io/rules/ | Spectral governance rulesets |
| apis.io/vocabularies/ | Provider tag vocabularies powering the advanced search |
| apis.io/examples/ | API usage examples |
| Section | What you'll find |
|---|---|
| apis.io/skills/ | Official Claude Agent Skill index — SKILL.md files published by providers, with per-skill and per-provider pages |
| apis.io/servers/ | Official Model Context Protocol server index — one page per MCP server, with install hints and source links |
| Section | What you'll find |
|---|---|
| apis.io/plans/ | API pricing-plan profiles (API Commons Plans format) |
| apis.io/rate-limits/ | API rate-limit profiles (API Commons Rate Limits format) |
| apis.io/finops/ | API FinOps profiles aligned with the FinOps Foundation FOCUS framework |
The same catalog is queryable programmatically, served as paths under the apex origin:
| Surface | URL |
|---|---|
| Search API (REST, metered & tiered) | apis.io/api/v1 — see apis.io/developer |
| MCP server (Streamable HTTP, tier-gated tools) | apis.io/mcp |
Access is metered, tiered, and monetized — a free tier plus paid tiers (GitHub OAuth sign-in, API keys, Stripe billing). The developer portal at apis.io/developer documents the endpoints, authentication, and tiers.
| Feed | URL |
|---|---|
RFC 9727 api-catalog linkset |
apis.io/.well-known/api-catalog |
llms.txt (agent overview) |
apis.io/llms.txt |
llms-full.txt (dense reference) |
apis.io/llms-full.txt |
| Sitemap index (all sections) | apis.io/sitemap_index.xml |
| APIs.json self-description | apis.io/apis.json |
Each catalog section also publishes its own llms.txt, sitemap.xml, and (where relevant) search-index.json for client-side search.
A central build pipeline (the network repo) reads from a set of upstream provider repos at github.com/api-evangelist — Git-versioned APIs.json profiles, one per provider — and emits Jekyll collections for every catalog. Each catalog is built independently, then synced into one S3 bucket and served through a single CloudFront distribution on apis.io; the search API and MCP server run as Lambdas behind API Gateway on the same origin.
Every provider, API, schema, and operational profile page carries:
- A 1–3 paragraph generated prose
overview, derived deterministically from the structured frontmatter (unique per page; no LLM-randomness) - Schema.org JSON-LD typed to the entity —
Organization+ItemListon providers,WebAPIon APIs,Dataseton schemas and operational profiles,CollectionPageon industry and region pages,BlogPostingon posts, all withBreadcrumbListsiblings - Open Graph and Twitter Card metadata
- Cross-page internal links — "Other APIs from this provider", "Related industries", "Related regions"
- A per-collection title suffix that telegraphs page type in SERPs (e.g.
Stripe Charges API — Documentation, OpenAPI | APIs.io APIs)
Providers also get a composite rating (0–100, banded Exemplar / Strong / Developing / Thin / Minimal) recomputed on every build — see apis.io/rating/.
- APIs.json (github.com/apis-json) — the machine-readable API discovery format this network is built on
- API Commons (github.com/api-commons) — the standard vocabulary of common API operational properties (plans, rate limits, etc.)
- api-evangelist — the upstream provider profile repos this network is built from
APIs.io, APIs.json, and API Commons are projects led by Kin Lane and Steve Willmott — open infrastructure for the next generation of API discovery. Email info@apievangelist.com for site-related questions, or open issues at github.com/apis-json and github.com/api-commons for spec-level questions.
The catalog is licensed for public use including search indexing, AI grounding / RAG, and model training — see apis.io/terms/.