msgspec-cbor

CBOR (RFC 8949) encoding and decoding for msgspec, backed by cbor2.

msgspec-cbor is a thin, pure-Python bridge that mirrors the msgspec.toml / msgspec.yaml wrapper modules: it lowers objects with msgspec.to_builtins, hands them to cbor2's native encoder, and validates decoded output back into your types with msgspec.convert. Rich types (datetime, bytes, Decimal, UUID, …) travel as real CBOR tags — never base64 or ISO strings.

Install

pip install msgspec-cbor

Usage

import msgspec
import msgspec_cbor

class Point(msgspec.Struct):
    x: int
    y: int

data = msgspec_cbor.encode(Point(1, 2))        # -> bytes
point = msgspec_cbor.decode(data, type=Point)  # -> Point(x=1, y=2)

Omit type= to decode into plain CBOR/Python objects with no validation.

Supported types

The default type table is the intersection of what cbor2 encodes as a native CBOR tag and what msgspec.convert accepts back — so every rich type round-trips losslessly.

Malformed input raises msgspec.DecodeError; a shape mismatch against type= raises msgspec.ValidationError. cbor2's own exceptions never escape the public API.

API

def encode(obj, *, enc_hook=None, order=None) -> bytes: ...
def decode(buf, *, type=Any, strict=True, dec_hook=None) -> Any: ...

The signatures mirror msgspec.toml / msgspec.yaml, so this is a drop-in sibling format.

order accepts msgspec's "deterministic" / "sorted" (lexicographic) plus "canonical", which emits CBOR canonical length-first key ordering (cbor2's canonical=True) for byte-exact wire formats.

Not affiliated

This is an independent bridge and is not affiliated with or endorsed by the msgspec project.

Attribution

• msgspec — BSD-3-Clause
• cbor2 — MIT

msgspec-cbor is MIT licensed and copies no code from either project.