MockServer           

MockServer is an HTTP(S) mock server and proxy for testing. Mock any HTTP/HTTPS, REST, gRPC, or JSON-RPC dependency; record-and-replay real traffic as a proxy; and drive it all from a client library (Java, Node, Python, Ruby) or a built-in dashboard. Recent releases add first-class LLM / AI-agent provider mocking (Anthropic, OpenAI, Gemini, Bedrock, Ollama and more), an MCP server for AI coding assistants, and chaos / fault injection on mocked and forwarded responses — see the changelog for what has shipped in each version.

Quick Start

Run MockServer with Docker in seconds:

docker run -d --rm -p 1080:1080 mockserver/mockserver

Then create your first expectation and call it (MockServer exposes a REST control plane on the same port):

# 1. Mock an endpoint: GET /hello -> 200 "Hello World"
curl -X PUT http://localhost:1080/mockserver/expectation \
  -H 'Content-Type: application/json' \
  -d '{
        "httpRequest":  { "method": "GET", "path": "/hello" },
        "httpResponse": { "statusCode": 200, "body": "Hello World" }
      }'

# 2. Call your mock
curl http://localhost:1080/hello
# -> Hello World

The same can be done from any client library or the dashboard at http://localhost:1080/mockserver/dashboard. For more configuration options see the Docker documentation.

Documentation

For usage guide please see: www.mock-server.com

Developer Documentation

Architecture, code structure, infrastructure, and operations documentation is available in the docs/ directory.

AI Integration

MockServer includes a built-in MCP server for AI coding assistant integration at /mockserver/mcp. See llms.txt and AI Integration docs.

Change Log

Please see: Change Log

Community

Discussions
Issues, Bugs & Feature Requests
Roadmap
Security

Requirements

Runtime: MockServer 6.x requires Java 17+. The minimum was raised from Java 11 as part of the Jakarta EE 10 / Spring 7 platform modernisation — see the Java 17 / Jakarta upgrade guide. If you are still on Java 11, pin to the 5.15.x line (no longer receiving security updates). The official Docker image already bundles a Java 17 runtime.

Building from source: requires JDK 17+; the produced bytecode targets Java 17.

Security Note: MockServer is a development and testing tool only. See SECURITY.md for important security considerations.

Versions

Maven Central

Maven Central contains the following MockServer artifacts under the org.mock-server groupId. Every artifact ships in two forms — -no-dependencies (shaded, zero transitive deps, recommended) and the plain form (transitive deps declared in the POM, for the rare case where you need to override versions yourself).

Server:

• mockserver-netty-no-dependencies / mockserver-netty — Netty-based HTTP(S) mock + proxy server (embed in tests or run standalone)
• mockserver-war — deployable WAR for hosting MockServer in a servlet container (mock mode)
• mockserver-proxy-war — deployable WAR for hosting MockServer in a servlet container (proxy mode)

Java client:

• mockserver-client-java-no-dependencies / mockserver-client-java — Java client for the MockServer REST API

Test framework integrations:

• mockserver-junit-rule-no-dependencies / mockserver-junit-rule — JUnit 4 @Rule
• mockserver-junit-jupiter-no-dependencies / mockserver-junit-jupiter — JUnit 5 extension (@MockServerSettings, @MockServerTest)
• mockserver-spring-test-listener-no-dependencies / mockserver-spring-test-listener — Spring TestExecutionListener
• mockserver-integration-testing-no-dependencies / mockserver-integration-testing — shared integration-test helpers

Build-tool plugin:

• mockserver-maven-plugin — Maven plugin to start, stop, and fork MockServer during the build lifecycle

Tip: The -no-dependencies artifacts bundle all dependencies into a single JAR with packages relocated under shaded_package.*, so they declare zero transitive dependencies. This avoids classpath conflicts with versions of Netty / Jackson / Guava / Bouncy Castle that your project already uses, and it removes the noise from CVE scanners flagging unused transitive dependencies. See the Maven Central page for full coordinates, snapshot repository setup, and the executable jar-with-dependencies form for command-line use.

6.0.0 breaking change: the <classifier>shaded</classifier> form has been removed. Replace mockserver-netty:<version>:shaded with mockserver-netty-no-dependencies:<version> (and likewise for the other shaded artifacts). The replacement produces the same shaded bytes; only the coordinates change.

SNAPSHOT builds are published to the Sonatype Central Portal snapshot repository at https://central.sonatype.com/repository/maven-snapshots/org/mock-server/.

Node Module & Grunt Plugin

NPM Registry contains the following module:

• mockserver-node - a Node.js module and Grunt plugin to start and stop MockServer
  
• mockserver-client-node - a Node.js client for both the MockServer and the proxy
  

Docker Hub

Docker Hub contains the following artifacts:

• MockServer Docker Container - a Docker container containing the Netty MockServer and proxy

Helm Chart

• MockServer Helm Chart - a Helm Chart that installs MockServer to a Kubernetes cluster (latest: 6.1.0). See the Install MockServer Helm Chart guide for all available versions and configuration options.

MockServer Clients

• mockserver-client-java - a Java client for both the MockServer and the proxy (use the -no-dependencies artifact to avoid transitive dependencies)
• mockserver-client-node - a Node.js and browser client for both the MockServer and the proxy
• mockserver-client-python - a Python client for both the MockServer and the proxy
• mockserver-client-ruby - a Ruby client for both the MockServer and the proxy

Community Tools

• MockServer Browser Admin - a React + TypeScript SPA for managing MockServer expectations via a web UI

Previous Versions

Issues

If you have any problems, please check the project issues and avoid opening issues that have already been fixed. When you open an issue please provide the following information:

• MockServer version (i.e. 6.1.0)
• How your running the MockServer (i.e maven plugin, docker, etc)
• MockServer log output, at INFO level (or higher)
• What the error is
• What you are trying to do

Contributions

Pull requests are, of course, very welcome! Please read our contributing to the project guide first. Then head over to the open issues to see what we need help with. Make sure you let us know if you intend to work on something. Also check out the project roadmap to see what is already in the backlog.

Feature Requests

Feature requests are submitted to GitHub issues and tracked on the project roadmap.

Maintainers

• James D Bloom