Arbiter Mock Server app icon Arbiter Mock Server · Android

Mock and debug your API, right on your device.

A powerful development and testing tool for Android developers. Intercept, mock, and debug network requests directly on your device — making API testing faster and more efficient.

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Features

Everything you need to test APIs

Intercept traffic, return custom responses, and inspect every request — all without a backend.

Request interception

Intercept HTTP/HTTPS requests in real-time and inspect headers, body, and response times.

Mock responses

Create custom responses with configurable JSON, status codes, and response delays.

Request logging

Comprehensive logging of all network activity with detailed request/response info.

Conditional mocking

Mock specific scenarios based on URL patterns, headers, or request parameters.

Pass-through mode

Forward requests to real servers when needed, with auto pass-through for unmatched calls.

Device IP mode

Share your mock server across the local network so multiple devices can test together.

Import / export

Share endpoint configurations and logs with your team through JSON import/export.

Privacy first

All data stays on your device. No external servers, no tracking, no analytics.

A look inside

See it in action

Tap any screenshot to take a closer look.

Arbiter dashboard with the mock server running on localhost
Start the server and copy your local URL in one tap
Add Endpoint screen with match type, mode and mock JSON response
Define endpoints with match rules, status codes and JSON
Request Logs screen showing headers and a formatted response body
Inspect every request and response in detailed logs
Create Endpoint from Log dialog turning a captured request into a mock
Turn any captured request into a mock endpoint instantly
Arbiter onboarding describing it as a mock server and middleware
Use it as a mock server, a middleware, or both
Onboarding steps explaining how to point your app at localhost
Point your app at localhost and you are ready to go
Built with

A lightweight, on-device stack

Flutter Dart SQLite HTTP Server
Use cases

Perfect for

Your data never leaves the device

No external servers, no tracking, no analytics — complete control over your data.

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