APIs.io API
APIs.io API
Read-only discovery API over the APIs.io catalog of providers, APIs, tags, artifacts, and curated dimensions — with a free discovery tier and a Pro synthesis tier.
A first-class, read-only discovery API over the APIs.io network.
The catalog is assembled from per-provider repositories and exposed here as the
providers, apis, and tags resources, a first-class collection per
artifact type (/openapis, /asyncapis, /arazzo, /postman, /json-schemas, …),
and a unified /search endpoint that spans them.
Design notes:
- Identifiers.
aidis the stable id. A provider istwilio; an API istwilio:twilio-accounts-api(<provider>:<api-slug>). - Artifacts by reference. API records carry a
propertieslist of artifacts (type+url). By default only references are returned; passinclude=contentto inline an artifact's body. - Selectable artifacts. Use
artifact_typesto return only the artifact types you care about (e.g.OpenAPI,Postman). - Free, Pro, and Business tiers. Raw discovery —
/search,/providers,/apis,/tags, the curated taxonomy dimensions (/industries,/regions,/areas),/resolve,/enrich,/vcs,/insights, and most artifact-type collections (/openapis,/mcp,/skills,/examples,/json-schemas, …) — is free. The rating data (/ratings,/providers/{slug}/rating), the ranked…/leadersviews within a dimension, the synthesis composites (/compare,/gaps,/changes), the per-company insight depth, the saved workspace (/me/*), and the high-value security artifact collections (/scopes,/security) are Pro./stackis freemium: free callers get the top pick per capability, Pro gets the full blueprint and/stack/export. Bulk dataset pulls (/export) are Business, the license tier above Pro. Each operation declares its tier viax-tier; the rubric (/ratings/rubric) stays free. SendX-API-Keyfor a paid tier; keyless callers get the free tier. A gated call returns 402 Payment Required (not 403 — CloudFront rewrites 403/404). Seex-apis-iofor the full tier / MCP-tool / skill map. - Also an MCP server + Agent Skills. Every operation maps 1:1 to an MCP tool at
https://apis.io/mcp(see each operation'sx-mcp-tool) and, where one exists, an Agent Skill (x-agent-skill). This is the API → MCP → Agent-Skill experience chain.
Tags
Providers
Organizations publishing APIs on the network.
APIs
Individual APIs, each owned by a provider and described by artifacts.
Tags
The tag taxonomy, with network-wide ranking metadata.
Industries
Industry verticals grouping providers across the catalog.
Regions
Geographic regions grouping providers across the catalog.
Areas
The API Evangelist areas taxonomy — curated topic collections (authentication, webhooks, payments, …), each a scored provider index with its own site. Pro.
Synthesis
Decision-grade composites over the catalog — provider comparison, gap analysis, catalog change feed, and recommended-stack design. Pro.
Ratings
The APIs.io API rating system — a 0–100 composite score, five bands, a trend marker, and six weighted facets measuring how complete, governed, and integration-ready each provider's public API surface is. Rubric v0.3.
Artifact Types
First-class, per-type artifact collections (OpenAPI, AsyncAPI, Arazzo, Postman, JSON Schema, and more). Each path filters and normalizes one artifact type across all providers.
Search
Unified cross-resource search.
Insights
Demand-side intelligence — what ~5,800 companies (Fortune 1000 + API providers) build, buy, and hire for around APIs, data, and AI, derived from job postings, press, and engineering blogs. Discovery is free; per-company depth, gaps, and provider matches are Pro.
Venture Capital
Venture-capital firms as a first-class entity — fund identity plus a network-matched, rated PORTFOLIO GRAPH. Browse firms, walk a fund's portfolio (filter to API providers / by rating band), and follow the reverse edge from a provider to the VCs that back it. Free discovery.
Resolve & Enrich
Agent ergonomics — resolve any identifier (domain, URL, GitHub org) to a provider, and enrich a provider in one call by choosing field groups. Free (the rating and insights enrichment groups are Pro).
Saved Workspace
A Pro dimension — per-user saved searches, lists, and net-new deltas. The same capability the MCP exposes as tools; turns apis.io from stateless lookup into a persistent research workspace. Requires an API key.
Export
Bulk data export — the license tier above Pro. The whole ratings or providers dataset in one pull, with the attribution string a published figure must carry. Business tier.