Bruno

Postman

postman.com

Popular

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

curl

curl/curl

Popular

Ubiquitous command-line tool and library (libcurl) for transferring data over HTTP and dozens of protocols.

Insomnia

Kong/insomnia

Kong's open-source API client for REST, GraphQL, gRPC and WebSockets with local or Git-synced storage.

Hoppscotch

hoppscotch/hoppscotch

Open-source, web-first API development ecosystem; a lightweight self-hostable Postman alternative.

HTTPie

httpie/cli

Human-friendly command-line HTTP client with JSON support and colorized output.

Yaak

mountain-loop/yaak

Rising

Fast, privacy-first desktop API client for REST, GraphQL, gRPC and WebSockets built with Tauri.

Posting

darrenburns/posting

Rising

Modern HTTP client that runs in the terminal as a keyboard-driven TUI with YAML-based collections.

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.