Can I send real HTTP requests?

Yes. The request builder sends a request only when you click Send. Requests that browsers block for cross-origin reasons go through a small relay that does not store anything.

Which OpenAPI versions are supported?

OpenAPI 3.0 and 3.1 in JSON or YAML. Swagger 2.0 files can be converted first.

Are these tools free to use?

Yes. Every tool is free, needs no account and has no usage limits beyond what your browser and device can handle.

API & HTTP tools

Everything for designing, testing and shipping APIs: OpenAPI contract linting, breaking-change diffs, consistency audits, schema and changelog generation, a live HTTP request builder, cURL converters, GraphQL viewers, webhook inspection and WebSocket testing.

16 tools in this category · 4 sub-categories

API & HTTP

HTTP Request Builder

Send live API requests and generate curl, fetch, axios snippets.

cURL to Fetch Converter

Convert a curl command into JavaScript fetch() code.

GraphQL Query Formatter

Format and indent GraphQL queries and mutations.

cURL Command Parser & Code Generator

Convert a curl command to fetch, Axios, Python, Go, PHP, Java, C#, Rust or Dart code.

Webhook Request Inspector

Inspect a pasted webhook request and verify its HMAC signature.

GraphQL Schema Viewer

Browse a GraphQL SDL schema's types, queries, and mutations.

WebSocket Tester

Open a live WebSocket connection, send frames and read replies.

OpenAPI

API Contract Analyzer

Lint an OpenAPI or Swagger spec for contract quality issues.

API Breaking Change Detector

Diff two OpenAPI specs and flag breaking changes.

API Consistency Auditor

Audit an API for naming, casing and response consistency.

API Changelog Generator

Generate a Markdown changelog from two OpenAPI versions.

Postman ↔ OpenAPI Converter

Convert a Postman collection to OpenAPI 3 and back again.

Other

OpenAPI / Swagger Validator

Validate OpenAPI 3.x / Swagger 2.0 documents in JSON or YAML.

WebSocket Frame Explainer

Decode WebSocket frame bytes into opcode, flags, mask and payload.

HAR File Analyzer

Analyse a HAR export: slow requests, errors, sizes and host breakdowns.

Schemas

API Response Schema Generator

Turn a JSON API response into OpenAPI, JSON Schema or TypeScript.

About api & http tools

Design, test and document APIs from one place. Lint OpenAPI contracts, detect breaking changes between versions, convert cURL commands to code, build HTTP requests and inspect webhooks and WebSocket traffic.