14 FORMAT, PROTOCOL & TOOL GUIDES
The languages of APIs.
Understand what each format does, when to use it, and where to find the source.
API descriptionOpenAPI
Describe HTTP endpoints, parameters, request bodies, and responses in a machine-readable document.
Read guide
API descriptionAsyncAPI
Describe message-driven APIs, including channels, operations, and message payloads.
Read guide
API descriptionSwagger / OpenAPI 2.0
A JSON or YAML format for describing HTTP APIs, commonly called Swagger 2.0.
Read guide
Query languageGraphQL
A query language and runtime for APIs, backed by a typed schema.
Read guide
AI integration protocolModel Context Protocol
An open protocol for connecting AI applications to tools, resources, and context.
Read guide
API descriptionAPI Blueprint
A Markdown-based language for describing web APIs and their interactions.
Read guide
Data schemaJSON Schema
A vocabulary for describing and validating the structure of JSON data.
Read guide
API conventionJSON:API
A specification for how clients request and modify resources and how servers respond in JSON.
Read guide
API descriptionRAML
A YAML-based language for describing RESTful APIs.
Read guide
API descriptionOpenRPC
A machine-readable description format for JSON-RPC 2.0 APIs.
Read guide
Data access protocolOData
A protocol for building and consuming data APIs with standardized query conventions.
Read guide
Event formatCloudEvents
A common format for describing event data across services and platforms.
Read guide
Request collectionPostman Collection
A reusable group of API requests, with configuration and scripts for working with them in Postman.
Read guide
API development toolInsomnia
An API client with import and export workflows for API specifications and request collections.
Read guideThese guides cover different layers of an integration. Description formats, data schemas, protocols, and request tools are not interchangeable.