msgspec

msgspec is a fast serialization and validation library, with builtin
support for JSON, MessagePack,
YAML, and TOML. It features:

• 🚀 High performance encoders/decoders for common protocols. The JSON and
  MessagePack implementations regularly
  benchmark as the fastest
  options for Python.

• 🎉 Support for a wide variety of Python types. Additional types may be
  supported through
  extensions.

• 🔍 Zero-cost schema validation using familiar Python type annotations. In
  benchmarks msgspec
  decodes and validates JSON faster than
  orjson can decode it alone.

• ✨ A speedy Struct type for representing structured data. If you already
  use dataclasses or
  attrs,
  structs should feel familiar.
  However, they’re
  5-60x faster
  for common operations.

All of this is included in a
lightweight library
with no required dependencies.

msgspec may be used for serialization alone, as a faster JSON or
MessagePack library. For the greatest benefit though, we recommend using
msgspec to handle the full serialization & validation workflow:

Define your message schemas using standard Python type annotations.

>>> import msgspec

>>> class User(msgspec.Struct):
...     """A new type describing a User"""
...     name: str
...     groups: set[str] = set()
...     email: str | None = None

Encode messages as JSON, or one of the many other supported protocols.

>>> alice = User("alice", groups={"admin", "engineering"})

>>> alice
User(name='alice', groups={"admin", "engineering"}, email=None)

>>> msg = msgspec.json.encode(alice)

>>> msg
b'{"name":"alice","groups":["admin","engineering"],"email":null}'

Decode messages back into Python objects, with optional schema validation.

>>> msgspec.json.decode(msg, type=User)
User(name='alice', groups={"admin", "engineering"}, email=None)

>>> msgspec.json.decode(b'{"name":"bob","groups":[123]}', type=User)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
msgspec.ValidationError: Expected `str`, got `int` - at `$.groups[0]`

msgspec is designed to be as performant as possible, while retaining some of
the nicities of validation libraries like
pydantic. For supported types,
encoding/decoding a message with msgspec can be
~10-80x faster than alternative libraries.

See the documentation for more information.

LICENSE

New BSD. See the
License File.