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

Over the wire test doubles

Eliminate API integration headaches with Specmatic's no-code AI-powered API development suite. Teams ship APIs 10x faster by transforming specifications into executable contracts instantly—no coding required, no integration surprises.

Camouflage is a backend mocking tool for HTTP, gRPC, Websockets and Thrift protocols, which helps you carry out your front end prototyping, unit testing, functional/performance testing in silos, in absence of one or more Microservices/APIs.

HTTP mock for Golang: record and replay HTTP/HTTPS interactions for offline testing

Java binding for Hoverfly

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

Service Virtualization Solution – a combined Service Stub and Transparent Proxy

AI-Mocks is a Kotlin-based mock server toolkit that brings service virtualization to both HTTP/SSE and LLM APIs — think WireMock meets local OpenAI/Anthropic/Gemini/A2A testing, but with real streaming and Server-Sent Events support.

A .Net Library for Hoverfly

Stubbing tool for HTTP calls to allow more comprehensive + deterministic tests

A fluent Java API for virtualizing HTTP services. Service virtualization simplified. No endpoint configuration. Import/export of request-response pairs.

Bokor is a simple, Record and Playback Mock Server written in Node.js, utilized for Service Virtualization.

Service Virtualized HTTP - to help service test automation stay fast and consistent

Stub and validate HTTP endpoints with ease.

Mokksy is advanced mock HTTP server built for testing applications using modern streaming APIs. Built for Java, Kotlin, and beyond.

Admin dashboard for Hoverfly

A mountebank client written in Go.

Servirtium Overview

Hoverfly integration for pytest