Industry standard API mocking for JavaScript.

Lightweight service virtualization/ API simulation / API mocking tool for developers and testers

HTTP/1.1, HTTP/2 and WebSockets stub server for stubbing distributed web services in Docker and non-containerized environments for integration and contract testing

Build and test APIs easily

High-performance, multi-protocol mock server. HTTP, WebSocket, gRPC, MQTT, SSE, GraphQL, SOAP in one binary.

Record & replay API responses for Playwright E2E tests — SSR proxy + browser HAR + WebSockets. Deterministic CI, no backend, no manual mocks.

Dynamic API, S3 & Mail mocking for web, mobile & microservice development.

Kotlin Multiplatform library for network inspection and mocking. Intercept HTTP and WebSocket traffic, mock API responses, and throttle requests.

Build web applications today against the GraphQL APIs of tomorrow.

Your API mocking tool for OpenAPI and AsyncAPI using Go and JavaScript - https://mokapi.io

A tool that enables you to - Generate fake data in formats like JSON, Python, JS, Ruby, PHP and SQL - Mock restful APIs with Bearer authentication without writing a single line of code with a drag and drop interface.

The first fetch/XMLHttpRequest network-mocking library that's actually user-friendly

Enterprise-grade webhook testing suite for developers. Capture, inspect, replay, forward, validate, and mock webhook traffic in real time without tunnels. Includes SSE live streaming, JSON Schema validation, and signature verification for Stripe, GitHub, Shopify, Slack, and custom HMAC workflows.

Governed API and agent runtime for desktop, VS Code, and CLI. Secure API testing, mocking, automation, secret protection, and controlled AI tool access.

A versatile Go tool for effortlessly generating mock HTTP APIs for all your needs.

A lightweight and easy to use RESTful api mocking server

Mock Service Worker Tools (MSW-Tools) is a data Mock tool built based on MSW.JS and Svelte. It is used for data linkage between front and back end interfaces, facilitating developers to perform functional tests in different data and scenarios.

A powerful fetch mocking library designed specifically for Bun tests

Web UI for WireMock - design stubs visually, group them into projects, persist to PostgreSQL, browse live stubs and logs, and publish in one click.

A lightweight, specification-first Go API mock server that generates realistic responses from OpenAPI 3.0 specifications.