JSON serialization with Pydantic

Web APIs speak JSON. Pydantic models convert cleanly to and from JSON text and bytes.

Model → JSON

from pydantic import BaseModel

class PingBody(BaseModel):
    message: str

body = PingBody(message="pong")
json_text: str = body.model_dump_json()
json_bytes: bytes = body.model_dump_json().encode("utf-8")

In FastAPI, returning a dict or a model often becomes JSON automatically; under the hood similar serialization runs.

JSON → model

raw = '{"message": "pong"}'
obj = PingBody.model_validate_json(raw)
assert obj.message == "pong"

model_validate accepts a dict; model_validate_json accepts a string.

Implement

1. Create a model for a {"status": "ok", "code": 200}-shaped object.
2. Serialize with model_dump_json(), parse back with model_validate_json.
3. Commit and push.