GeezerVison

A free and open-source fake API designed for testing and prototyping, with Python for added flexibility.

Custom API & Rule Engine
Instantly generate a custom API from a JSON object and customize its behavior with a Python rule engine. Define rules to handle errors, modify HTTP responses, headers, and bodies using Python scripts—all for free and open source. Access the source code to set up your own local instance.

How to Create a Custom API?
MockAPY, available on GitHub, lets you create a local mock API with custom rules. Alternatively, you can generate an API online using the editors below, but without custom rules. The API will be immediately accessible but is deleted once a day. If needed, you can recreate it on this page. For frequent usage, consider setting up a local API to avoid limitations.

Documentation

Routes

Configuration of the resources

All resources must be contained within a single JSON object, where each attribute represents a resource holding an array of elements.

In this example, two resources have been created: "products" and "users", each containing two elements.

{
  "products": [
    {
      "id": "1", "name": "T-shirt", "price": 19.99
    },
    {
      "id": "2", "name": "Jeans", "price": 49.99
    }
  ],
  "users": [
    {
      "id": "1", "username": "johndoe", "email": "[email protected]"
    },
    {
      "id": "2", "username": "janedoe", "email": "[email protected]"
    }
  ]
}

Configuration of the rules

Custom rules are defined using Python code, allowing you to set conditions based on the request (e.g., HTTP method, headers, and payload) and control the response (including HTTP status code and payload). This enables you to customize the API's behavior for specific testing and development needs.

Rules are executed before the API processes data (reading, writing, or deleting).

The HTTP status and payload specified in the rules override those defined by the API.

Here is an example of a rule that returns an HTTP status 401 when accessing the resource /products/23:

import request
import response
import json

def handle_request():
    if request.pathname() == "/products/23":
        response.status(401)
        response.exit()

The exit method indicates whether to halt after applying the rule or to continue with the API execution.

Input

The input object is used to represent the different criteria that can be tested in the request.

Output

The output object is used to update the response if the rule match.

Why use a mock API when developing with Python?

Using a Mock API is incredibly useful when developing web applications with Python, especially with Django, Flask, and FastAPI. It allows developers to simulate API responses, which is helpful for testing applications even when the actual API is unavailable or still under development. It also makes it much easier to handle error scenarios such as timeouts, HTTP 500 errors, or invalid responses. Hopefully, this simple yet powerful Mock REST API tool will be useful to you!