Wiremock - A tool for mocking HTTP services

WireMock is a simulator for HTTP-based APIs. Some might consider it a service virtualization tool or a mock server. It enables you to stay productive when an API you depend on doesn't exist or isn't complete. It supports testing of edge cases and failure modes that the real API won't reliably produce. And because it's fast it can reduce your build time from hours down to minutes.

It supports HTTP response stubbing, matchable on URL, header and body content patterns, Request verification, Fault injection, Per-request conditional proxying, Configurable via a fluent Java API, JSON files and JSON over HTTP and lot more.