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TypeSpec

TypeSpec is an API description language developed by Microsoft for defining API shapes that compile to OpenAPI, JSON Schema, Protobuf, and other output formats. It provides a language and toolchain for describing REST APIs, gRPC services, and data schemas in a type-safe, composable way with built-in support for versioning, metadata, and extensibility via decorators and libraries.

TypeSpec publishes 6 APIs on the APIs.io network. Tagged areas include API Design, Code Generation, OpenAPI, Protocol Buffers, and Specification Language.

The TypeSpec catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

TypeSpec’s developer surface includes documentation, engineering blog, release notes, and 15 more developer resources.

🌐 Visit website 📡 Source on GitHub
32.2/100 thin ▬ flat Agent 6/100 agent aware self hosted · MIT Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0
AccessFreemium
6 APIs 1 MCP Servers
API DesignCode GenerationOpenAPIProtocol BuffersSpecification Language

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0
Composite quality — 32.2/100 · thin
Contract Quality 3.3 / 23
Developer Ergonomics 3.2 / 18
Access Clarity 2.8 / 18
Operational Transparency 4.3 / 12
Contract Governance 2.7 / 11
Discoverability 5.8 / 9
Open Source Surface 10.0 / 10
Agent readiness — 6/100 · agent aware
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
Documented Reversibility 0 / 6
MCP Server 12 / 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
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Delegated User Identity 0 / 6
Protected Resource Metadata 0 / 5
Registration Without a Human 0 / 6
Agentic Commerce Well-Known Document 0 / 5
Open Source Surface applies to this provider. This product is open source and we read its repository directly, so Open Source Surface carries 10 points of the composite. It is scored from what the repository actually publishes — a security policy, a contribution guide, a release history, a code of conduct — read live from the provider rather than inferred from our own catalog pointers. This facet adds; nothing was taken away to make room for it. An open-source project is not excused from the commercial facets, because exemption would strip it of the points it does earn. If we have the wrong repository, or this product is not open source, say so on your provider repo and we will drop the facet rather than have you publish against it.
Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.
The six quality facets above are damped to 90 points between them, because the conditional facet above carries the other 10. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 90% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/typespec: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 6

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

TypeSpec Compiler

The TypeSpec compiler processes `.tsp` TypeSpec files and emits output for configured emitters (OpenAPI, JSON Schema, Protobuf, etc.). It provides a programmatic Node.js/TypeScr...

TypeSpec OpenAPI Emitter

The TypeSpec OpenAPI emitter converts TypeSpec definitions to OpenAPI 3.0 specifications. It supports HTTP operations, request/response bodies, security schemes, and API version...

TypeSpec JSON Schema Emitter

Emits JSON Schema documents from TypeSpec model definitions, enabling data validation and type documentation workflows.

TypeSpec Protobuf Emitter

Emits Protocol Buffer `.proto` files from TypeSpec service definitions, enabling gRPC service generation from a single TypeSpec source.

TypeSpec HTTP Library

The TypeSpec HTTP library provides decorators and types for describing HTTP REST APIs including routes, operations, request bodies, query parameters, headers, and response codes.

TypeSpec REST Library

The TypeSpec REST library provides decorators for REST API patterns including resource operations (CRUD), collection operations, and standardized error response shapes.

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

MCP Server

MCP SERVER

Pricing Plans 1

Published pricing tiers and plan structures.

Typespec Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Typespec Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Typespec Finops

FINOPS

Semantic Vocabularies 1

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

Typespec Context

15 classes · 11 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

TypeSpec API Rules

5 rules · 3 warnings 2 info

SPECTRAL

JSON Schema 1

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

TypeSpec Program

3 properties

JSON SCHEMA

JSON Structure 1

JSON Structure definitions describing this provider's data shapes.

Typespec Model Structure

8 properties

JSON STRUCTURE

Security Posture 1

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

Typespec Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Documentation 3

Reference material describing how the API behaves

ContributionGuide
ContributionGuide
 Documentation
Documentation
 JSONSchema
JSONSchema

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

MCPServer
MCPServer

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

JSONLD
JSONLD
 Vocabulary
Vocabulary

Build 3

SDKs, sample code, and the tooling you integrate with

CodeOfConduct
CodeOfConduct
 GitHubOrganization
GitHubOrganization
 npm
npm

Access & Security 2

Authentication, authorization, and security posture

SecurityPolicy
SecurityPolicy
 DomainSecurity
DomainSecurity

Operate 3

Status, limits, changes, and where to get help

IssueTracker
IssueTracker
 Community
Community
 ReleaseNotes
ReleaseNotes

Commercial 1

Pricing, plans, and the legal terms of use

License
License

Company 2

The organization behind the API

Website
Website
 Blog
Blog

Other 1

Properties that don't map to a standard resource type

Playground
Playground

Source (apis.yml)

apis.yml Raw ↑ 
aid: typespec
name: TypeSpec
description: TypeSpec is an API description language developed by Microsoft for defining API shapes that compile to OpenAPI,
  JSON Schema, Protobuf, and other output formats. It provides a language and toolchain for describing REST APIs, gRPC services,
  and data schemas in a type-safe, composable way with built-in support for versioning, metadata, and extensibility via decorators
  and libraries.
type: Index
deliveryModel:
  model: self-hosted
  license: MIT
  open_source: true
  commercial: false
  callable_host: false
  label: Self-hosted open source · you run it yourself
  confidence: high
  source:
  - license
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://typespec.io/img/favicon.svg
tags:
- API Design
- Code Generation
- OpenAPI
- Protocol Buffers
- Specification Language
url: https://raw.githubusercontent.com/api-evangelist/typespec/refs/heads/main/apis.yml
created: '2026-03-25'
modified: '2026-05-19'
specificationVersion: '0.23'
apis:
- aid: typespec:typespec-compiler
  name: TypeSpec Compiler
  description: The TypeSpec compiler processes `.tsp` TypeSpec files and emits output for configured emitters (OpenAPI, JSON
    Schema, Protobuf, etc.). It provides a programmatic Node.js/TypeScript API for building TypeSpec tooling, custom emitters,
    and compilers.
  humanURL: https://typespec.io/docs
  tags:
  - API Design
  - Code Generation
  - Compiler
  - Specification Language
  properties:
  - type: Documentation
    url: https://typespec.io/docs
  - type: GitHubRepository
    url: https://github.com/microsoft/typespec
  - type: npm Package
    url: https://www.npmjs.com/package/@typespec/compiler
  - type: GettingStarted
    url: https://typespec.io/docs/getting-started/getting-started-rest
  - type: Language Reference
    url: https://typespec.io/docs/language-basics/overview
- aid: typespec:typespec-openapi-emitter
  name: TypeSpec OpenAPI Emitter
  description: The TypeSpec OpenAPI emitter converts TypeSpec definitions to OpenAPI 3.0 specifications. It supports HTTP
    operations, request/response bodies, security schemes, and API versioning decorators.
  humanURL: https://typespec.io/docs/emitters/openapi3/reference
  tags:
  - Code Generation
  - OpenAPI
  - REST API
  properties:
  - type: Documentation
    url: https://typespec.io/docs/emitters/openapi3/reference
  - type: npm Package
    url: https://www.npmjs.com/package/@typespec/openapi3
  - type: GitHubRepository
    url: https://github.com/microsoft/typespec/tree/main/packages/openapi3
- aid: typespec:typespec-json-schema-emitter
  name: TypeSpec JSON Schema Emitter
  description: Emits JSON Schema documents from TypeSpec model definitions, enabling data validation and type documentation
    workflows.
  humanURL: https://typespec.io/docs/emitters/json-schema/reference
  tags:
  - Code Generation
  - JSON-Schema
  - Validation
  tags_raw:
  - Code Generation
  - JSON Schema
  - Validation
  properties:
  - type: Documentation
    url: https://typespec.io/docs/emitters/json-schema/reference
  - type: npm Package
    url: https://www.npmjs.com/package/@typespec/json-schema
- aid: typespec:typespec-protobuf-emitter
  name: TypeSpec Protobuf Emitter
  description: Emits Protocol Buffer `.proto` files from TypeSpec service definitions, enabling gRPC service generation from
    a single TypeSpec source.
  humanURL: https://typespec.io/docs/emitters/protobuf/reference
  tags:
  - Code Generation
  - gRPC
  - Protocol Buffers
  properties:
  - type: Documentation
    url: https://typespec.io/docs/emitters/protobuf/reference
  - type: npm Package
    url: https://www.npmjs.com/package/@typespec/protobuf
- aid: typespec:typespec-http-library
  name: TypeSpec HTTP Library
  description: The TypeSpec HTTP library provides decorators and types for describing HTTP REST APIs including routes, operations,
    request bodies, query parameters, headers, and response codes.
  humanURL: https://typespec.io/docs/libraries/http/reference
  tags:
  - Decorators
  - HTTP
  - REST API
  properties:
  - type: Documentation
    url: https://typespec.io/docs/libraries/http/reference
  - type: npm Package
    url: https://www.npmjs.com/package/@typespec/http
- aid: typespec:typespec-rest-library
  name: TypeSpec REST Library
  description: The TypeSpec REST library provides decorators for REST API patterns including resource operations (CRUD), collection
    operations, and standardized error response shapes.
  humanURL: https://typespec.io/docs/libraries/rest/reference
  tags:
  - Decorators
  - Resource Pattern
  - REST API
  properties:
  - type: Documentation
    url: https://typespec.io/docs/libraries/rest/reference
  - type: npm Package
    url: https://www.npmjs.com/package/@typespec/rest
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
common:
- type: IssueTracker
  url: https://github.com/microsoft/typespec/issues
- type: SecurityPolicy
  url: https://github.com/microsoft/typespec/blob/main/SECURITY.md
- type: CodeOfConduct
  url: https://github.com/microsoft/typespec/blob/main/CODE_OF_CONDUCT.md
- type: ContributionGuide
  url: https://github.com/microsoft/typespec/blob/main/CONTRIBUTING.md
- type: License
  name: MIT
  url: https://github.com/microsoft/typespec/blob/main/LICENSE
- type: DomainSecurity
  url: security/typespec-domain-security.yml
- type: Website
  url: https://typespec.io
- type: Documentation
  url: https://typespec.io/docs
- type: GitHubOrganization
  url: https://github.com/microsoft/typespec
- type: npm
  url: https://www.npmjs.com/package/@typespec/compiler
- type: Playground
  url: https://typespec.io/playground
- type: Blog
  url: https://typespec.io/blog
- type: Community
  url: https://github.com/microsoft/typespec/discussions
- type: ReleaseNotes
  url: https://github.com/microsoft/typespec/releases
- type: JSONLD
  url: json-ld/typespec-context.jsonld
- type: Vocabulary
  url: vocabulary/typespec-vocabulary.yml
- type: JSONSchema
  url: json-schema/typespec-program-schema.json
- name: MCP Server
  url: https://github.com/microsoft/typespec-mcp
  type: MCPServer

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