Open Source API Mocking Platform

🚀 Mock APIs in 30 Seconds

Chrome Extension for instant interception. HTTP Server for dynamic mocking. Two tools, one ecosystem.

Mock APIs in 30 seconds with JSON Schema + Faker, MCP integration, and stateful workflows.

Mockzilla HTTP Server
GET /api/users
POST /api/products
PUT /api/orders/123
{
  "id": "{{faker.string.uuid()}}",
  "name": "{{faker.person.fullName()}}",
  "email": "{{faker.internet.email()}}"
}
Mockzilla Extension
/api/usersHits: 5
Type: JSON | Status: 200
/api/products/*Hits: 2
Type: JSON | Status: 200
✓ Intercepting fetch() and XMLHttpRequest
$ docker run -d -p 36666:36666 -v mockzilla-data:/app/data --name mockzilla andrecrjr/mockzilla:latest

Quick Installation

Choose your tool and start mocking in seconds

HTTP Server

Docker-based mock server

$ docker run -d -p 36666:36666 -v mockzilla-data:/app/data --name mockzilla andrecrjr/mockzilla:latest

Chrome Extension

Browser-based interception

Intercept fetch() and XMLHttpRequest in real-time

  • ✓ Flexible pattern matching
  • ✓ JSON & text responses
  • ✓ Hit tracking & analytics
  • ✓ Sync with HTTP Server

Your server will be available at http://localhost:36666

Mockzilla HTTP Server

Next.js + PostgreSQL mock server

A powerful, self-hosted mock server that lets you create dynamic API endpoints with JSON Schema interpolation, wildcard routes, and stateful workflows. Perfect for teams that need reliable, consistent mock data during development.

Mini-Database

Scenario-based data persistence with PostgreSQL. Store and query mock data like a real database.

MCP Integration

First-class support for AI agents. 24 Model Context Protocol tools for Claude, Cursor, and more.

Workflow Scenarios

Complex stateful scenarios that simulate multi-step API interactions and user flows.

$ docker pull andrecrjr/mockzilla:latest
✓ Latest version ready
GET /api/users
{
  "id": "usr_abc123",
  "name": "{{faker.person.fullName()}}",
  "email": "{{faker.internet.email()}}",
  "role": "admin",
  "created_at": "2024-01-15T10:30:00Z"
}
Folders
Organize mocks
Workflows
Stateful scenarios
MockzillaMockzilla Extensionv1.0.0
/api/users
JSON
{ "users": [{ "id": 1, "name": "John" }] }
Hits: 5Enabled
/api/products/*
JSON
{ "products": [{ "id": 42, "price": 29.99 }] }
Hits: 2Enabled
+ Add Rule

Mockzilla Chrome Extension

Browser-based API interception

A lightweight Chrome extension that intercepts fetch() and XMLHttpRequest calls in real-time, allowing you to mock API responses without any server setup. Perfect for frontend developers who need instant feedback.

Real-time Interception

Intercept fetch() and XMLHttpRequest instantly as they happen in your browser.

Flexible Matching

Pattern-based matching with wildcards, regex, and exact URL matching.

Hit Tracking

Track how many times each mock rule is triggered with built-in analytics.

Cross-device Sync

Sync your mock rules across machines with the HTTP Server integration.

Install from Chrome Web Store →

Platform Features

Two powerful tools working together as one ecosystem

HTTP Server

JSON Schema + Faker

Define mock data using JSON Schema with built-in Faker.js interpolation for dynamic, realistic responses.

HTTP Server

PostgreSQL-Powered

Reliable data persistence with PostgreSQL. Store and manage all your mocks in a mini-database.

HTTP Server

Wildcard Variants

Create flexible route patterns with wildcard support. Match multiple URL patterns with a single mock.

HTTP Server

Workflow Mode

Build stateful scenarios with workflow mode. Simulate complex API interactions and multi-step processes.

HTTP Server

MCP Integration

24 Model Context Protocol tools for AI agents. Seamlessly integrate with Claude Desktop, Cursor, and more.

Extension

Real-time Interception

Intercept fetch() and XMLHttpRequest in real-time. Mock API responses instantly in your browser.

Extension

Flexible Matching

Pattern-based matching with wildcards, regex, and exact URL matching for precise control.

Extension

Hit Tracking

Track how many times each mock rule is triggered with built-in analytics and counters.

Both Products

Cross-device Sync

Sync your mock rules across machines with the HTTP Server integration for team collaboration.

24
MCP Tools
<30s
Deploy Time
2
Products
100%
Open Source

How Mockzilla Works

Three simple steps to start mocking like a pro

1

Choose Your Tool

Use the HTTP Server for dynamic mocking, the Chrome Extension for instant interception, or both together for the full experience.

HTTP ServerChrome ExtensionBoth (Recommended)
2

Configure Mocks

Define your mock endpoints with static JSON, dynamic schemas with Faker.js, or stateful workflow scenarios.

Static JSONJSON Schema + FakerWorkflows
3

Use in Development

Point your frontend to Mockzilla and start building. The Chrome Extension intercepts calls automatically when synced.

Frontend DevQA TestingAI Agents

Your Development Stack

Your Frontend App
React, Vue, Angular, etc.
fetch() / XHR
HTTP Server
Dynamic mocks
Extension
Interception
Real-time responses
No backend required
Sync across devices

AI-Ready with MCP Integration

Mockzilla exposes 24 Model Context Protocol tools, allowing AI agents to interact with your mocks programmatically. Perfect for testing AI-powered workflows.

Claude Desktop
Cursor
Windsurf
Custom MCP Clients
MCP Tools Available
✓ list_folders
✓ create_folder
✓ get_mocks
✓ create_mock
✓ update_mock
✓ delete_mock
✓ manage_workflows
+ 17 more tools...

Frequently Asked Questions

Everything you need to know about Mockzilla