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W3C

The World Wide Web Consortium (W3C) is the main international standards body for the World Wide Web, founded by Tim Berners-Lee in 1994. W3C develops web standards and guidelines to ensure the long-term growth of the Web, focusing on accessibility, internationalization, privacy, and security. W3C specifications include HTML, CSS, XML, SVG, WebAssembly, ARIA, WCAG, JSON-LD, Verifiable Credentials, and hundreds of other foundational web technologies. W3C operates through Working Groups, Interest Groups, and Community Groups that develop specifications through a consensus-based process, resulting in W3C Recommendations.

agent aware

Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.

Kin Score

API Evangelist profiles W3C the way a machine reads it — 26 machine-readable artifacts across 15 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.

Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — W3C scores 44.6/100 (thin), with a separate agent-readiness read of 39/100 (agent aware). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.

Kin Score

This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 44.6/100 · thin
Contract Quality 13.6 / 25
Developer Ergonomics 0.4 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 4.8 / 13
Governance 10.4 / 12
Discoverability 7.5 / 10
Agent readiness — 39/100 · agent aware
Machine-Readable Contract 18 / 18
Agentic Access Contract 15 / 15
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3

How we profile W3C

Each block below is one kind of artifact we hold for W3C. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.

APIs 15

Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.

Individual APIs this provider publishes, each with its own machine-readable definition.

W3C API

The W3C API provides programmatic access to W3C data including specifications, working groups, editors, translations, and affiliations. It enables developers to query W3C's cata...

Web Content Accessibility Guidelines (WCAG)

WCAG is the international standard for web accessibility, providing guidelines for making web content more accessible to people with disabilities. WCAG 2.2 is the current Recomm...

HTML Living Standard

The HyperText Markup Language specification maintained by WHATWG as a living standard, published as a W3C Recommendation. HTML defines the semantic structure of web pages and fo...

CSS Specifications

The Cascading Style Sheets (CSS) specification family maintained by the W3C CSS Working Group. CSS defines the presentation and styling of HTML documents. Key modules include CS...

JSON-LD

JSON-LD (JSON for Linking Data) is a W3C Recommendation for encoding linked data using JSON. It provides a way to add semantic meaning to JSON documents through the use of @cont...

Verifiable Credentials

The Verifiable Credentials Data Model is a W3C Recommendation enabling cryptographically secure, privacy-respecting digital credentials. The VC family includes the data model, d...

WebAssembly

WebAssembly (Wasm) is a W3C Recommendation defining a portable binary instruction format for a stack-based virtual machine. It enables near-native performance in web browsers fo...

WAI-ARIA

Accessible Rich Internet Applications (WAI-ARIA) is a W3C Recommendation defining a set of HTML attributes that define ways to make web content and web applications more accessi...

RDF and SPARQL

The Resource Description Framework (RDF) is a W3C standard for representing information in the web. RDF 1.2 and SPARQL 1.2 are the latest versions, providing the foundation for ...

Digital Credentials API

The W3C Digital Credentials API provides browser support for mediating presentation and issuance of digital credentials such as digital identity documents. It enables web applic...

W3C Affiliations API

The Affiliations API from W3C — 2 operation(s) for affiliations.

W3C Ecosystems API

The Ecosystems API from W3C — 1 operation(s) for ecosystems.

W3C Groups API

The Groups API from W3C — 2 operation(s) for groups.

W3C Specifications API

The Specifications API from W3C — 3 operation(s) for specifications.

W3C Translations API

The Translations API from W3C — 1 operation(s) for translations.

Scroll within the panel for all 15 ·

Open Collections 1

Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

W3C API

OPEN COLLECTION

Pricing Plans 1

Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.

Published pricing tiers and plan structures.

W3C Plans Pricing

3 plans

PLANS

Rate Limits 1

Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.

Documented rate limits and quota policies.

W3C Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.

Cost, billing, and metering signals for API financial operations.

W3C Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.

JSON-LD contexts and semantic vocabularies used across these APIs.

W3C Context

0 classes · 19 properties

JSON-LD

Spectral Rules 2

Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.

W3C API Rules

5 rules · 3 warnings

SPECTRAL

W3C API Rules

7 rules · 3 warnings

SPECTRAL

JSON Schema 1

Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.

Standalone JSON Schema definitions for this provider's data models.

W3C Technical Report

12 properties

JSON SCHEMA

JSON Structure 1

JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.

JSON Structure definitions describing this provider's data shapes.

W3C Specification Structure

0 properties

JSON STRUCTURE

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.

Authentication, domain security, vulnerability disclosure, and trust-center signals.

W3C Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.

Recommended x-agentic-access execution contracts for AI agents.

W3C Agentic Access

9 operations

9 operations · 0 acting

AGENTIC

Resources

Every other property we hold for W3C — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

Design & Contract 3

Pagination, idempotency, versioning, errors, and events

Build 1

SDKs, sample code, and the tooling you integrate with

Access & Security 1

Authentication, authorization, and security posture

Learn 1

Tutorials, courses, talks, and written guidance

← All providers · Data indexed from github.com/api-evangelist/w3c · machine-readable index on apis.io