pyserde

library0.32.1pypypi✓ verified 24d ago

PySerde is a Python serialization/deserialization library built on top of dataclasses, inspired by Rust's Serde. It allows for declarative definition of data structures and automatically generates serialization and deserialization functions for various formats like JSON, YAML, TOML, and MessagePack. Currently at version 0.31.2, it maintains an active release cadence with frequent bug fixes and minor feature additions.

serialization

pip install pyserde

github ↗package ↗

INSTALL

IMPORT

SIG · PYSERDE

pyserde

serializationpythonv0.32.1

Install

3.7s avg

Import

450ms

Disk

41MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v0.32.1 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.910 runs

installs and imports cleanly · install 0.0s · import 0.460s · 41.6MB

glibc

py 3.10–3.910 runs

installs and imports cleanly · install 3.7s · import 0.440s · 43MB

41MB installed

● package 41MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

serde

✓ from serde import serde

field

✓ from serde import field

to_json

✓ from serde.json import to_json

from_json

✓ from serde.json import from_json

Decorate a dataclass with `@serde` to enable serialization and deserialization. Use format-specific functions like `to_json` and `from_json` from `serde.json`. The `@serde` decorator also adds `to_dict()` and `from_dict()` methods directly to the class for generic dictionary conversion.

from dataclasses import dataclass from serde import serde, field from serde.json import to_json, from_json @serde @dataclass class User: name: str age: int = field(default=30) email: str | None = None # Create an instance user_instance = User(name="Alice", email="alice@example.com") # Serialize to JSON string json_string = to_json(user_instance) print(f"Serialized JSON: {json_string}") # Deserialize from JSON string deserialized_user = from_json(User, json_string) print(f"Deserialized User: {deserialized_user}") # The @serde decorator also adds to_dict() and from_dict() methods directly to the class user_dict = user_instance.to_dict() print(f"Converted to dict: {user_dict}") another_user = User.from_dict({"name": "Bob", "age": 25, "email": "bob@example.com"}) print(f"Created from dict: {another_user}")

Debug

Known issues

breakingPySerde version 0.31.2 and later requires Python 3.10 or newer. Attempting to install or use these versions on older Python interpreters will result in an installation error.

fix

Upgrade your Python interpreter to 3.10+ to use the latest versions of pyserde.

affects: >=0.31.2

gotchaTo use serialization/deserialization for specific formats (e.g., YAML, TOML, faster JSON backends like `orjson`), you must install `pyserde` with the corresponding extras. The base `pip install pyserde` only includes JSON support via Python's standard `json` library.

fix

Install `pyserde` with the necessary extras, e.g., `pip install 'pyserde[json,yaml,orjson]'`.

affects: All

gotchaThe `@serde` decorator is designed to be applied to `dataclasses.dataclass` (or `attrs` classes when using `serde_attrs`). It will not work on plain Python classes, as it relies on the metadata and structure provided by dataclasses.

fix

Ensure your classes are defined as dataclasses (or `attrs` classes) before applying `@serde`.

affects: All

gotchaAdvanced field options such as `skip_if_none`, `skip_if_default`, `flatten`, `skip_serializing`, and `skip_deserializing` were introduced in versions 0.29.0 and 0.30.0. If you rely on these specific features, ensure your `pyserde` installation is version 0.30.0 or later.

fix

Upgrade `pyserde` to 0.30.0 or later to utilize all advanced field customization options.

affects: <0.30.0

Errors

Common errors & fixes

error: can't find rust-src component

pyserde's underlying Rust components require the `rust-src` toolchain component, which is not installed by default with Rust.

fix

rustup component add rust-src

ModuleNotFoundError: No module named 'serde'

The Python library is named `pyserde`, so imports must specify `pyserde` instead of just `serde`.

fix

from pyserde import serde, field, to_json, from_json

SerdeError: Class MyData is not a serde class. Please make sure you have `@serde` decorator on top of your dataclass.

The `@serde` decorator was omitted, preventing `pyserde` from generating the necessary serialization and deserialization methods for the dataclass.

fix

from dataclasses import dataclass
from pyserde import serde, to_json

@serde
@dataclass
class MyData:
    value: int

data = MyData(value=1)
print(to_json(data))

TypeError: Object of type datetime is not JSON serializable

Python's standard `json` module, used by `pyserde` by default for JSON serialization, cannot serialize `datetime` objects without a custom encoder.

fix

from dataclasses import dataclass
from datetime import datetime
from pyserde import serde, field, to_json

@serde
@dataclass
class Event:
    timestamp: datetime = field(
        serializer=lambda dt: dt.isoformat(),
        deserializer=lambda s: datetime.fromisoformat(s)
    )

event = Event(timestamp=datetime.now())
print(to_json(event))

Upgrade

Version history

0.32.1latest on PyPI · released Aug 29, 2026

Audit

Dependencies

pyyamloptionalRequired for YAML serialization/deserialization. Install with `pyserde[yaml]`.

tomloptionalRequired for TOML serialization/deserialization. Install with `pyserde[toml]`.

orjsonoptionalOptional faster JSON backend. Install with `pyserde[orjson]`.

ujsonoptionalOptional faster JSON backend. Install with `pyserde[ujson]`.

msgpackoptionalRequired for MessagePack serialization/deserialization. Install with `pyserde[msgpack]`.

Agent activity

9 hits · last 30 days

node

Resources

githubhttps://github.com/yukinarit/pyserde ↗

packagehttps://pypi.org/project/pyserde/ ↗