Karate

Postman

postman.com

Popular

Dominant API platform for sending requests, organizing collections, mocking and automated API tests.

REST Assured

rest-assured/rest-assured

Popular

Java DSL for testing REST services with given/when/then syntax, standard in JVM API test suites.

SuperTest

forwardemail/supertest

Popular

HTTP assertion library for testing Node.js servers (Express, Fastify, Koa) without opening ports.

Newman

postmanlabs/newman

Command-line collection runner for Postman, used to execute API test collections in CI.

Pact

pact-foundation/pact-js

Consumer-driven contract testing for HTTP and messaging so microservices can deploy independently.

Hurl

Orange-OpenSource/hurl

Rising

Runs and tests HTTP requests defined in a simple plain-text format; easy to version and run in CI.

Schemathesis

schemathesis/schemathesis

Trending (detected automatically)

Property-based API testing that generates thousands of test cases from OpenAPI or GraphQL schemas.

Bruno

usebruno/bruno

Trending

Offline-first, Git-friendly API client that stores collections as plain-text files in your repo.