The source for apicommons.org — the home of the open, machine-readable building blocks of API operations and a family of browser-first API tools. Part of the APIs.io network.
API Commons began as a machine-readable artifact for declaring the licensing of your API, and has grown into a shared library of operational properties — getting started, authentication, plans, SDKs, road maps, change logs, support, governance rules, and more. It works in concert with APIs.json to turn the human-readable properties of your API operations into machine-readable building blocks you can use to standardize and automate your API ecosystem at scale. The premise: if we are going to take things to the next level with APIs and AI, there are aspects of API operations we need to stop competing on and start sharing.
This is the Jekyll site published to apicommons.org. It carries both the building blocks and the index of tools:
_common/— Common Schema: shared operational properties every API can adopt._community/— Community Schema: community-contributed properties._blueprints/— reusable API blueprints._overlays/— OpenAPI Overlays for applying properties to existing descriptions._rulesets//rules//rulesets/— governance rules and rulesets.onboarding/— agentic API onboarding building blocks._posts/— the API Commons blog._data/,_includes/,_layouts/,assets/,images/— site data and theme.tools/— the index of the API Commons tool family (below).scripts/— helpers that generate site data (e.g. rulesets from the API Commons rule catalog).
Each building block is a machine-readable property or artifact that describes one facet
of API operations — designed to be referenced from an apis.json / apis.yml index so
both humans and agents can consume it. Each lives in its own repo under
github.com/api-commons.
- policies — the business rules behind API governance.
- rules — Spectral rulesets across many artifact types.
- guidance — the how-to layer that turns governance rules into help.
- lifecycle — the stages every API moves through.
- teams — the people layer of API operations.
- experiences — the developer experiences an API program offers.
- use-cases — the use cases an API serves.
- vocabulary — shared words and definitions for API operations.
- plans — access plans, tiers, and pricing.
- change-log — publish an API's changelog, machine-readably.
- road-map — publish an API's roadmap, machine-readably.
- interface-license — apply an open license to your API's interface (its surface, not its implementation).
- api-onboarding — the API Onboarding Descriptor (AID), a
/.well-known/api-onboardingdocument describing what it takes to onboard with an API. - api-authorization — a jurisdiction-neutral, two-tier, machine-checkable profile for securing APIs with OAuth 2.1 and FAPI 2.0.
- problem-details-for-http-apis — a base for using RFC 9457 Problem Details in your API.
- json-api — schemas and governance for the JSON:API standard.
- train-travel — an OpenAPI + APIs.json template for a Train Travel API, handy for demos and testing.
- examples — shared examples for the building blocks and the APIs.json ecosystem.
- snacks-twilio-messages — an API Snack for AI: send a message with Twilio.
Browser-first, backend-free tools for working with the APIs you produce and consume — everything runs locally in your browser, so your tokens and data never leave it. Each tool lives at its own subdomain of apicommons.org:
| Tool | Where | What it does |
|---|---|---|
| Agent Rule Export | agents.apicommons.org | Export a ruleset into agent-native artifacts — AGENTS.md block, system prompt, remediation prompt pack, and a compact rule digest. |
| API Discovery | discovery.apicommons.org | Search APIs.io and Git hosts for API artifacts and roll them into one APIs.json 0.21 index. |
| API Documentation | documentation.apicommons.org | Standalone docs for any APIs.json — OpenAPI as a full reference, Arazzo as step timelines. |
| API Experience | experience.apicommons.org | A DX/AX layer for any APIs.json — trace each REST operation to its MCP tool and Agent Skill, with a free/paid coverage scorecard. |
| API Governance Graph | graph.apicommons.org | Bind rules, policies, provenance, guidance, experiences, and lifecycle into one navigable graph, with a Gaps view. |
| API Governance MCP | github.com/api-commons/api-governance-mcp | The AI surface of the Validator — the same Spectral governance over MCP for any agent. |
| API Reusability | reusability.apicommons.org | Score how reusable your organization's APIs really are, by org, team, or domain. |
| API Validator | validator.apicommons.org | Browser-first governance linter for OpenAPI (3.x + Swagger 2.0), AsyncAPI, Arazzo, and JSON Schema, powered by Spectral. |
| Code-First Governance | codefirst.apicommons.org | Govern generated specs — fingerprint the OpenAPI generator, separate findings you must fix in code from spec-authoring ones, and map each to the annotation that fixes it. |
| Context Gate | contextgate.apicommons.org | Choose which API operations and fields you expose to agents; emit a governed Tyk API + MCP surface and a Spectral ruleset for it (PII, secrets, compliance). |
| Governance Baseline | baseline.apicommons.org | Adopt governance on a legacy estate — snapshot today's violations, then fail only NEW ones while you burn the baseline down. |
| Governance Certification | certification.apicommons.org | Issue and verify tamper-evident governance certificates — a SHA-256 fingerprint lets consumers re-verify an API passed a ruleset at a profile. |
| Governance Coverage | coverage.apicommons.org | Measure how much of your API description your rules actually check — coverage by section, dead rules, and per-rule reach. |
| Governance Pipeline | github.com/api-commons/governance-pipeline | A forkable reference API governance pipeline — PR-gated, SHA-pinned, OWASP security job. |
| Governance Pipeline Auditor | auditor.apicommons.org | Score a repo's Spectral CI against an 8-point governance maturity rubric. |
| Governance Scorecard | scorecard.apicommons.org | The longitudinal view — ingest Spectral snapshots over time and score governance health per spec (0–100), with trends. |
| Governance Waivers | waivers.apicommons.org | Sanctioned, owned, expiring governance exceptions — reconcile a waivers file against Spectral output; expired, stale, and expiring waivers surface. |
| MCP Install | install.apicommons.org | A universal install button for MCP servers — one button, every client. |
| Model Library | library.apicommons.org | A versioned, reusable model/component library — see which specs consume each model and classify a version bump as breaking or not across every consumer. |
| Ruleset Commons | rulesets.apicommons.org | A registry of adoptable, provenanced governance rulesets you can extends. |
| Spec Review | review.apicommons.org | A ref-resolving design-diff for OpenAPI/AsyncAPI/Arazzo — resolve $ref, flag breaking changes, and get a copyable Markdown summary for the PR. |
| Spectral OWASP Ruleset | github.com/api-commons/spectral-owasp-ruleset | A grounded Spectral ruleset for the OWASP API Security Top 10. |
| Spectral Reporter | reporter.apicommons.org | Turn a Spectral lint run into a self-contained HTML governance report (with SARIF + trends). |
| Spectral Ruleset Studio | studio.apicommons.org | Turn a prose style guide into an owned, grounded, well-named Spectral ruleset. |
| Toolsmith | toolsmith.apicommons.org | Forge MCP tools and Agent Skills from your OpenAPI — a workbench for designing the agent layer of an API. |
See the full, current list at apicommons.org/tools.
New here? Start with the hub, then dig into the tools or the building blocks.
Tools — browser-first, backend-free apps
- apicommons.org/tools — the full, current index
- validator.apicommons.org · studio.apicommons.org · graph.apicommons.org · reporter.apicommons.org — a few to start with
Building blocks — machine-readable properties of API operations
Specs — schemas, profiles, and templates
The network
- github.com/api-commons — every repo, each released independently
- apis.io — the API discovery network API Commons is part of
- apisjson.org — the APIs.json discovery format
- Questions or contributions — open an issue
A project of API Evangelist, maintained openly under API Commons. The building blocks and tools are open and free to use; API Evangelist offers expert API governance and strategy services around them.