Overview

msgspec 0.7, released on June 20, 2022, accelerates JSON string decoding and optimizes memory allocations.

Main Features

Accelerated JSON decoding

JSON string decoding is optimized with a new SIMD parser, offering 2-5x gains over the previous version.

python 
import msgspec

# Fast decoding of large JSON responses
class Item(msgspec.Struct):
    id: int
    name: str
    price: float

data = b'[{"id":1,"name":"A","price":9.99}]'
items = msgspec.json.decode(data, type=list[Item])
print(items[0].price)  # 9.99

Memory optimization

Memory allocations are reduced during decoding, lowering garbage collector pressure.

python 
import msgspec

# Reusable decoder to reduce allocations
dec = msgspec.json.Decoder(type=dict)

for line in open('data.jsonl', 'rb'):
    obj = dec.decode(line)
    # processing...

Sources