Overview

msgspec 0.19, released on December 27, 2024, brings 40% faster JSON, __replace__ support, and drops Python 3.8.

Main Features

Faster JSON and __replace__

The JSON decoder is 40% faster. The __replace__ method (Python 3.13 copy/replace protocol) is supported on Structs.

python 
import msgspec
import copy

class Config(msgspec.Struct):
    host: str = 'localhost'
    port: int = 8000
    debug: bool = False

cfg = Config()
# __replace__: copy with modifications
prod = copy.replace(cfg, host='0.0.0.0', debug=False)
print(prod)  # Config(host='0.0.0.0', port=8000, debug=False)

Sources