json-fix

1.0.2 verified Mon Apr 27 auth: no python

A library that allows custom JSON serialization for any class by adding a __json__ method, seamlessly patching the built-in json module. Current version 1.0.2, updated periodically.

pip install json-fix

Common errors

error TypeError: Object of type MyClass is not JSON serializable ↓

cause The import 'import json_fix' is missing or the class does not have a __json__ method.

fix

Add 'import json_fix' at the top of your script and define a __json__ method on your class that returns a serializable object.

error json_fix not found ↓

cause The package is not installed.

fix

Run 'pip install json-fix' to install the package.

Warnings

breaking json_fix patches the built-in json module globally. If other code relies on the original behavior (e.g., raising TypeError on non-serializable objects), it may break. ↓

fix Ensure no other code depends on json raising TypeError for custom objects without __json__.

gotcha The __json__ method must return a JSON-serializable object (dict, list, string, etc.), not a raw JSON string. Returning a string will double-encode it. ↓

fix Return a native Python object (e.g., dict) from __json__; do not call json.dumps inside it.

gotcha json_fix only works with the built-in json module. It does not affect third-party serializers like orjson, rapidjson, or ujson. ↓

fix Use built-in json module for serialization when using json_fix.

Imports

json_fix
wrong
```
from json_fix import ...
```
correct
```
import json_fix
```
Simply importing the module patches json; no direct symbol needed.

Quickstart

Imports json_fix to patch json module, then defines a class with __json__ method for custom serialization.

import json
import json_fix

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    def __json__(self):
        return {"name": self.name, "age": self.age}

person = Person("Alice", 30)
print(json.dumps(person))  # {"name": "Alice", "age": 30}