Typing Stubs for simplejson

Warnings

• gotcha The `types-simplejson` package provides *only* type-checking stubs. For actual runtime functionality, you *must* also install the `simplejson` library separately.
  Fix: Ensure `simplejson` is installed in your environment alongside `types-simplejson`: `pip install simplejson`.
• gotcha Do not attempt to import directly from `types_simplejson`. The imports for your code should always reference the `simplejson` library itself.
  Fix: Always use `import simplejson` (or `from simplejson import ...`) in your code. `types-simplejson` provides the type hints behind the scenes to your type checker.
• gotcha Version compatibility between `types-simplejson` and the runtime `simplejson` library is crucial for accurate type checking. This stub package aims to provide accurate annotations for `simplejson==3.20.*`.
  Fix: Align your `simplejson` installation to match the version range specified by the `types-simplejson` metadata (e.g., `pip install 'simplejson>=3.20,<3.21'`).
• breaking The `simplejson` library (version 3.19.1) introduced a breaking change by setting the default value of the `allow_nan` parameter in `dumps` and `dump` to `False`.
  Fix: If your application relies on serializing or deserializing `NaN`, `Infinity`, or `-Infinity` values, you must explicitly set `allow_nan=True` in your `simplejson.dumps()` or `simplejson.dump()` calls.
• gotcha Typeshed stubs, including `types-simplejson`, are built and tested against specific Python versions. This package requires Python >=3.10 and is validated against Python versions 3.10 to 3.14.
  Fix: Ensure your project's Python interpreter is within the supported range (Python 3.10-3.14) to guarantee proper type-checking behavior and avoid unexpected errors.

Install

• pip install types-simplejson Install types-simplejson
• pip install simplejson Install runtime dependency

Imports

• simplejson

  import simplejson

  This package provides static type-checking annotations for the `simplejson` library. You should import `simplejson` directly for runtime usage and type hints will be automatically picked up.
• JSONDecodeError

  from simplejson import JSONDecodeError

Quickstart

Demonstrates basic usage of `simplejson` with type hints provided by `types-simplejson`. The code serializes a dictionary to a JSON string and then deserializes it back to a dictionary, with type annotations for clarity and static analysis.

import simplejson
from typing import Any, Dict, Union

def serialize_and_deserialize(data: Dict[str, Union[str, int, bool]]) -> Dict[str, Any]:
    """
    Serializes a dictionary to a JSON string and then deserializes it.
    """
    json_string: str = simplejson.dumps(data, indent=2, sort_keys=True)
    print(f"Serialized JSON:\n{json_string}")
    deserialized_data: Dict[str, Any] = simplejson.loads(json_string)
    print(f"Deserialized data: {deserialized_data}")
    return deserialized_data

if __name__ == "__main__":
    my_data = {"name": "Alice", "age": 30, "is_student": False}
    result = serialize_and_deserialize(my_data)
    assert result == my_data