MockMyAPI 🚀

Automatic API discovery, intelligent mock generation, and instant local backend server for frontend developers.

MockMyAPI analyzes your frontend codebase (React, Vue, Angular, Next.js, Svelte, etc.), automatically discovers API endpoints called via fetch() or axios, generates realistic mock JSON responses using intelligent field inference, and launches a local FastAPI server that your frontend can immediately interact with.

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⚡ Quick Start (TL;DR)

# Install package
pip install mock-my-api

# Option A: Scan & serve in a single command
mock-my-api scan ./frontend --serve

# Option B: Run via OpenAPI 3.x spec directly
mock-my-api openapi ./openapi.yaml --serve

Your frontend can now immediately send HTTP calls to http://localhost:5050!

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💡 Why MockMyAPI?

Frontend development frequently stalls waiting for backend endpoints to be built, deployed, or stabilized. MockMyAPI solves this bottleneck by turning your frontend source code directly into a functional mock server:

• Zero Manual Setup: Scans JavaScript, TypeScript, JSX, and TSX files to find API calls automatically.
• Intelligent Data Generation: Recognizes field names (email, avatar, price, inStock, createdAt) and uses Faker to populate contextually accurate mock JSON.
• Preserves Custom Responses: Merges newly discovered endpoints into .mock-my-api.yaml without overwriting your manually edited mock data.
• Stateful In-Memory CRUD: Test real data mutations (POST, PUT, PATCH, DELETE) with live in-memory state persistence.
• Failure State Simulation: Test frontend resilience with latency (slow), random HTTP error codes (errors), or service unavailability (offline).
• OpenAPI 3.x Integration: Parse OpenAPI specifications (.yaml or .json) with full $ref resolution and example extraction.
• Hybrid Proxy Fallback: Forward unmatched API requests to your live staging/production backend seamlessly.

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🔄 Architecture & Data Flow

Frontend API Calls (fetch / axios)
                │
                ▼
      MockMyAPI AST & Regex Scanner
                │
                ▼
   Endpoint Normalization & Deduplication
     (`/api/users/${id}` → `/api/users/:id`)
                │
                ▼
      Fake Data & Type Inference Engine
   (Faker field resolution + Resource templates)
                │
                ▼
     .mock-my-api.yaml (Configuration)
                │
                ▼
      FastAPI Dynamic Server + Middleware
     (CORS + Redaction + Logging + Scenarios)
                │
                ▼
Frontend Receives Realistic Mock Responses

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📦 Installation

pip install mock-my-api

Requires Python 3.9 or higher.

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💻 Detected Frontend Code Patterns

MockMyAPI automatically scans .js, .ts, .jsx, .tsx, .mjs, and .cjs files, ignoring node_modules, .git, dist, build, .next, and build outputs.

1. Standard Fetch Calls

fetch("/api/users");
fetch(`/api/users/${userId}`);
fetch("/api/orders", { method: "POST", body: JSON.stringify(data) });

2. Axios Method Calls

axios.get("/api/users");
axios.post("/api/orders", data);
axios.put(`/api/users/${id}`, data);
axios.delete("/api/users/1");

3. Custom Axios Instances

const api = axios.create({
    baseURL: "/api/v1"
});

api.get("/products"); // Discovered as: /api/v1/products
api.post("/orders", data);

Common instance variable names detected automatically: api, http, client, service, httpClient, apiClient.

4. Axios Configuration Objects

axios({
    method: "POST",
    url: "/api/auth/login",
    data: { username, password }
});

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📖 Detailed CLI Command Reference

mock-my-api scan <directory>

Scans the frontend source code and generates or merges .mock-my-api.yaml.

mock-my-api scan ./frontend

Options:

Flag	Short	Description	Default
--serve	-s	Immediately start the mock server after scanning	false
--port	-p	Server port	5050
--host	-h	Server host address	127.0.0.1
--stateful		Enable stateful in-memory CRUD operations	false
--scenario		Activate simulation scenario (slow, errors, offline)	None
--proxy		Backend URL to forward unmatched requests to	None
--verbose	-v	Enable detailed request header/query logging	false

---

mock-my-api serve

Launches the local FastAPI mock backend server using .mock-my-api.yaml.

mock-my-api serve --port 5050

Options:

Flag	Short	Description	Default
--port	-p	Server port	5050
--host	-h	Server host address	127.0.0.1
--stateful		Maintain in-memory state across CRUD operations	false
--scenario		Activate simulation scenario (slow, errors, offline)	None
--proxy		Real backend URL for proxy fallback	None
--config	-c	Custom path to configuration file	.mock-my-api.yaml
--openapi	-o	Import OpenAPI spec file before launching server	None
--verbose	-v	Enable verbose request logging in terminal	false

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mock-my-api openapi <spec-file>

Generates mock endpoints directly from an OpenAPI 3.x specification (.yaml or .json).

mock-my-api openapi ./openapi.yaml --serve

• Extracts explicit example / examples from schema properties.
• Resolves internal JSON references ($ref: '#/components/schemas/User').
• Automatically populates missing response fields using Faker.

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mock-my-api doctor

Runs interactive health checks verifying your development setup.

mock-my-api doctor

Checks performed:

• ✅ Python version compatibility
• ✅ .mock-my-api.yaml syntax & structure validity
• ✅ Route collisions & duplicate path detection
• ✅ Port 5050 availability check
• ✅ Installed dependency health check

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🛠️ Advanced Features

1. Stateful In-Memory CRUD Mode (--stateful)

When launching with --stateful, MockMyAPI maintains a live in-memory store for endpoints matching standard resource conventions (e.g., /api/users, /api/users/:id).

mock-my-api serve --stateful

• GET /api/users: Returns initial user collection.
• POST /api/users: Assigns auto-incrementing id and adds item to collection.
• GET /api/users/101: Retrieves created item by ID.
• PUT /api/users/101 / PATCH /api/users/101: Updates item attributes in-memory.
• DELETE /api/users/101: Removes item from collection.

2. Simulation Scenarios (--scenario)

Simulate real-world network failure conditions to verify frontend resilience:

# Inject 1-3 seconds of latency into every response
mock-my-api serve --scenario slow

# Randomly return HTTP errors (400, 401, 403, 404, 429, 500, 503) on 30% of requests
mock-my-api serve --scenario errors

# Simulate service outage with 503 errors and Retry-After headers
mock-my-api serve --scenario offline

You can also specify endpoint-level delay or error rates in .mock-my-api.yaml:

endpoints:
  - method: GET
    path: /api/checkout
    delay: 1500        # 1.5 seconds delay
    error_rate: 0.2    # 20% error chance

3. Proxy Fallback Mode (--proxy)

If your frontend makes calls to endpoints not yet configured in .mock-my-api.yaml, MockMyAPI transparently forwards those requests to a real backend:

mock-my-api serve --proxy https://api.staging.example.com

• Local mock responses take priority.
• Unmatched endpoints are proxied to https://api.staging.example.com.
• Hop-by-hop headers (Host, Connection, Transfer-Encoding) are filtered safely.

4. Automatic Sensitive Data Redaction

MockMyAPI terminal logs automatically redact sensitive headers and body fields to prevent leaking credentials in terminal output or video recordings:

• Redacted Headers: Authorization, Cookie, Set-Cookie, X-API-Key, X-Auth-Token
• Redacted Body Fields: password, secret, token, api_key, credit_card, ssn

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⚙️ Configuration Reference (.mock-my-api.yaml)

version: 1
server:
  host: 127.0.0.1
  port: 5050
  cors: true
  cors_origins:
    - "*"
  verbose: false

endpoints:
  - method: GET
    path: /api/users
    status: 200
    delay: 0
    error_rate: 0.0
    response:
      - id: 1
        name: Rahul Sharma
        email: rahul@example.com
        avatar: https://dummyimage.com/300x300
        active: true
        created_at: "2026-07-21T10:30:00Z"

  - method: POST
    path: /api/orders
    status: 201
    response:
      id: 101
      status: created
      total: 1499.00

  - method: DELETE
    path: /api/users/:id
    status: 204
    response: null

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🧪 Development & Testing

Clone the repository and install in editable mode:

git clone https://github.com/buntychakraborty/mock-my-api.git
cd mock-my-api
python3 -m pip install -e ".[dev]"

Run the complete test suite:

pytest -v

All 26 unit and end-to-end integration tests verify scanner accuracy, path normalization, fake data inference, FastAPI route handler generation, stateful CRUD, proxy fallback, and scenario execution.

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📄 License

Distributed under the MIT License. See LICENSE for more details.