A Flutter plugin for running and configuring a local, mock HTTP server that allows your mobile app to simulate calls to a REST API.

Android iOS
Support SDK 23+ (Target SDK 36) 13.0+

Quick Start 🚀

Head to the quick start guide to get up and running, or jump straight to a specific topic:

To hit the ground running

(1) Create your Mockzilla server config and add mocked endpoints.

final mockzillaConfig = MockzillaConfig().addEndpoint(
    () => EndpointConfig(
        name: "Hello world",
        endpointMatcher: (request) => request.uri.endsWith("/hello-world"),
        defaultHandler: (request) => const MockzillaHttpResponse(
            body: jsonEncode(const HelloWorldResponse())),
        ),
        errorHandler: (request) => const MockzillaHttpResponse(
            statusCode: 418,
        ),
    ),
);

(2) Start the mock server!

// Make sure to call this before starting Mockzilla!
WidgetsFlutterBinding.ensureInitialized();

await Mockzilla.startMockzilla(mockzillaConfig);

Why's it useful? 🙌

Development servers go down, endpoints can be late being delivered or not exist at all! Mockzilla aims to easily provide a way of simulating your server from within your mobile application's codebase.

Advantages

✅ Compile safe mock endpoint definitions.

✅ HTTP client agnostic.

✅ Works completely offline.

✅ Entirely self-contained in your application's codebase.

✅ Edit responses live from a desktop app or an in-app overlay — no rebuild required.

✅ Presets for one-tap switching between success, error, and edge-case responses.

Control mocks live, while your app runs 🎛️

Beyond defining mocks in code, Mockzilla ships two ways to change what's returned while your app is running — force an endpoint to fail, add artificial latency, or apply a preset, all without touching code or rebuilding:

alt text

Why not use a hosted solution? ☁️

Hosted mocking solutions can be powerful mocking tools in many cases. They have their downsides:

  1. They can go down, Mockzilla works offline!
  2. There's no compile-time checking
  3. They require active maintenance with no compile-time safety if APIs change.

Important Note 🛑

Mockzilla is designed as a development and test tool only.

Mockzilla should never be used in production. Its traffic is unprotected and by nature of running a server on device, it can introduce security issues. Advice on how to do this using different Dart entrypoints can be found here.

Do not ship it to production.

Contributing

Contributions are welcome! See CONTRIBUTING.md for how to get set up.

Libraries

mockzilla