What is MockServer used for?

MockServer is an open-source HTTP(S) mock server and proxy for testing that mocks APIs, inspects and modifies live traffic, and injects failures. It is a good fit for mocking APIs for testing, recording and replaying traffic, and chaos testing and failure injection.

Is MockServer open source?

Yes. MockServer is open source under the Apache-2.0 licence. Its source code is on GitHub at mock-server/mockserver-monorepo and is written mainly in Java.

Yes. MockServer is open source, so the software itself is free to use.

Can I self-host MockServer?

Yes. MockServer can be self-hosted on your own server or infrastructure.

What is MockServer an alternative to?

MockServer is an open-source alternative to Webhook.site, Beeceptor, Mockaroo and WireMock Cloud. Other open-source alternatives to Webhook.site include Mocky and Insomnia Mockbin.

Is MockServer actively maintained?

Yes. The most recent commit to MockServer was on 14 October 2026. The project has 5k stars on GitHub.

MockServer: open-source alternative to Webhook.site

About MockServer

MockServer is an HTTP(S) mock server and proxy designed for testing. It allows mocking APIs, inspecting and modifying live traffic, and injecting failures. It supports multiple protocols including HTTP/1.1, HTTP/2, gRPC, WebSockets, TCP, and more on a single port, with additional support for HTTP/3, message brokers, and AI/LLM APIs.

The tool is open-source and can be used for various testing scenarios such as creating expectations, stateful scenarios, chaos testing, load/performance testing, and contract testing. It also provides features for recording and replaying traffic, verifying requests, and integrating with AI assistants via MCP.

Key features

Mock any HTTP service and record traffic
Support for HTTP/1.1, HTTP/2, HTTP/3, HTTPS, gRPC, WebSockets, TCP, and more
Inspect and modify live traffic
Inject failures for chaos testing
Record and replay traffic
MCP server for AI assistants

Good fit for

Mocking APIs for testing
Recording and replaying traffic
Chaos testing and failure injection

Built with: Java tools; Python tools
Tags: mock-server; http; proxy; testing; api; grpc

MockServer: questions and answers

What is MockServer used for?: MockServer is an open-source HTTP(S) mock server and proxy for testing that mocks APIs, inspects and modifies live traffic, and injects failures. It is a good fit for mocking APIs for testing, recording and replaying traffic, and chaos testing and failure injection.
Is MockServer open source?: Yes. MockServer is open source under the Apache-2.0 licence. Its source code is on GitHub at mock-server/mockserver-monorepo and is written mainly in Java.
Is MockServer free?: Yes. MockServer is open source, so the software itself is free to use.
Can I self-host MockServer?: Yes. MockServer can be self-hosted on your own server or infrastructure.
What is MockServer an alternative to?: MockServer is an open-source alternative to Webhook.site, Beeceptor, Mockaroo and WireMock Cloud. Other open-source alternatives to Webhook.site include Mocky and Insomnia Mockbin.
Is MockServer actively maintained?: Yes. The most recent commit to MockServer was on 14 October 2026. The project has 5k stars on GitHub.