jsonyx

jsonyx is a customizable JSON library for Python 3.10+. It is written in pure Python with an optional C extension for better performance and no dependencies. The documentation for jsonyx is available online at: https://jsonyx.readthedocs.io

Key Features

• JSON decoding, encoding and patching
• Pretty printing:

  {
      "foo": [1, 2, 3],
      "bar": {"a": 1, "b": 2, "c": 3}
  }

• Optionally supports these JSON deviations using jsonyx.allow:

  {
      /* Block */ // and line comments
      "Decimal numbers": [1.0000000000000001, 1e400],
      "Duplicate keys": {"key": "value 1", "key": "value 2"},
      "Missing commas": [1 2 3],
      "NaN and infinity": [NaN, Infinity, -Infinity],
      "Surrogates": "\ud800",
      "Trailing comma": [0,],
      "Unquoted keys": {key: "value"}
  }

• Detailed error messages:

  Traceback (most recent call last):
    File "/Users/wannes/Downloads/broken.json", line 1, column 99-381
      ...sList": {"GlossEntry": {"ID": "SGM..."GML", "XML"]}, "GlossSee": "markup"
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  jsonyx.JSONSyntaxError: Unterminated object
  

• Dedicated functions for reading and writing files and pretty printing

Benchmark

We recommend to use orjson or msgspec for performance critical applications:

encode	json	jsonyx	msgspec	orjson	rapidjson	unit (μs)
List of 256 booleans	4.82	4.11	1.16	1.00	3.12	1.85
List of 256 ASCII strings	14.71	12.73	1.67	1.00	10.12	3.64
List of 256 floats	23.47	23.54	1.38	1.00	24.87	8.57
List of 256 dicts with 1 int	10.87	11.17	1.48	1.00	6.30	8.54
Medium complex object	9.90	9.76	1.24	1.00	7.31	14.48
List of 256 strings	26.73	14.99	2.26	1.00	34.28	13.69
Complex object	7.80	5.55	1.00	inf1	6.92	205.10
Dict with 256 lists of 256 dicts with 1 int	9.58	10.23	1.27	1.00	5.32	2517.22

decode	json	jsonyx	msgspec	orjson	rapidjson	unit (μs)
List of 256 booleans	3.40	5.24	2.06	1.00	2.42	2.03
List of 256 ASCII strings	1.68	2.05	1.12	1.00	1.59	13.11
List of 256 floats	6.58	7.38	1.45	1.00	5.71	10.25
List of 256 dicts with 1 int	2.36	2.84	1.38	1.00	2.22	32.11
Medium complex object	2.89	3.70	1.23	1.00	2.62	33.99
List of 256 strings	1.02	1.00	2.74	2.04	2.99	64.38
Complex object	1.12	1.04	1.06	1.00	1.23	1061.41
Dict with 256 lists of 256 dicts with 1 int	1.66	1.91	1.14	1.00	1.47	17536.25

Footnotes

1. failed due to recursion error ↩