JSON to Python: Complete Guide to Dataclasses, Pydantic, and JSON Parsing

Parse JSON in Python with dataclasses or Pydantic. Here's the complete guide. Standard json Module import json from typing import Any # Parse JSON string data : dict [ str , Any ] = json . loads ( json_string ) # Parse JSON file with open ( ' data.json ' ) as f : data = json . load ( f ) # Serialize to JSON json_string = json . dumps ( data , indent = 2 ) # Python → JSON type mapping: # str → string, int/float → number, bool → boolean # list → array, dict → object, None → null Python Dataclasses from dataclasses import dataclass , field , asdict from typing import Optional @dataclass class User : id : int name : str email : str bio : Optional [ str ] = None tags : list [ str ] = field ( default_factory = list ) def from_dict ( cls , data : dict ): return cls ( ** { k : data [ k ] for k in data if k in cls . __dataclass_fields__ }) user = from_dict ( User , json . loads ( json_string )) print ( asdict ( user )) # Back to dict Pydantic v2 (Recommended) from pydantic import BaseModel , Fi