jiter

Fast iterable JSON parser.

jiter Permissive license MIT Active ★ 539 v0.16.0 released 2026-06-29

Install

jiter on PyPI

pip

pip install jiter

uv

uv add jiter

poetry

poetry add jiter

Package facts

License	MIT (permissive)
Python support	supports the current Python release (>=3.9)
Install friction	medium — platform-specific wheel
Runtime dependencies	none
Maintenance	actively maintained — 45 days since the last release
Last repo commit	2026-06-29
First released	2024-05-16
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: jiter-0.16.0-cp310-cp310-macosx_10_12_x86_64.whl; jiter-0.16.0-cp310-cp310-macosx_11_0_arm64.whl; jiter-0.16.0-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; jiter-0.16.0-cp310-cp310-manylinux_2_17_armv7l.manylinux2014_armv7l.whl; jiter-0.16.0-cp310-cp310-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl; jiter-0.16.0-cp310-cp310-manylinux_2_17_s390x.manylinux2014_s390x.whl; jiter-0.16.0-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl; jiter-0.16.0-cp310-cp310-manylinux_2_31_riscv64.whl; jiter-0.16.0-cp310-cp310-manylinux_2_5_i686.manylinux1_i686.whl; jiter-0.16.0-cp310-cp310-musllinux_1_1_aarch64.whl; jiter-0.16.0-cp310-cp310-musllinux_1_1_x86_64.whl; jiter-0.16.0-cp310-cp310-win32.whl; jiter-0.16.0-cp310-cp310-win_amd64.whl; jiter-0.16.0-cp311-cp311-macosx_10_12_x86_64.whl; jiter-0.16.0-cp311-cp311-macosx_11_0_arm64.whl; jiter-0.16.0-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; jiter-0.16.0-cp311-cp311-manylinux_2_17_armv7l.manylinux2014_armv7l.whl; jiter-0.16.0-cp311-cp311-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl; jiter-0.16.0-cp311-cp311-manylinux_2_17_s390x.manylinux2014_s390x.whl; jiter-0.16.0-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl

Development Status :: 4 - BetaEnvironment :: ConsoleEnvironment :: MacOS XFramework :: Pydantic :: 2Intended Audience :: DevelopersIntended Audience :: Information TechnologyIntended Audience :: System AdministratorsOperating System :: POSIX :: LinuxOperating System :: UnixProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: GraalPyTopic :: File Formats :: JSON

About jiter

from the package's own PyPI description — quoted content, verbatim

jiter

CI (image) pypi (image) versions (image) license (image)

This is a standalone version of the JSON parser used in pydantic-core. The recommendation is to only use this package directly if you do not use pydantic.

The API is extremely minimal:

```python def from_json( json_data: bytes, /, *, allow_inf_nan: bool = True, cache_mode: Literal[True, False, 'all', 'keys', 'none'] = 'all', partial_mode: Literal[True, False, 'off', 'on', 'trailing-strings'] = False, catch_duplicate_keys: bool = False, float_mode: Literal['float', 'decimal', 'lossless-float'] = 'float', ) -> Any: """ Parse input bytes into a JSON object.

Arguments:
    json_data: The JSON data to parse
    allow_inf_nan: Whether to allow...

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AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

A fast, minimal JSON parser that deserializes bytes into Python objects, with options for partial parsing, duplicate key detection, and different float representations.

Medium install friction due to compiled wheels across many platforms (CPython 3.9–3.14, multiple architectures). No runtime dependencies. Active maintenance with recent releases and a healthy repository signal.

MIT license permits commercial and private use with minimal restrictions—suitable for most projects.

Usage

import jiter

json_data = b'{"name": "John", "age": 30}'
parsed = jiter.from_json(json_data)
print(parsed)  # {'name': 'John', 'age': 30}

Requires Python ≥3.9; input must be bytes, not a string.

Verdict: A lean, actively maintained JSON parser designed for speed with zero runtime dependencies. Medium install friction is offset by broad platform coverage and permissive MIT licensing. No known vulnerabilities and suitable for projects seeking a lightweight alternative to the standard library when pydantic is not in use.

Needs verification

Actual performance comparison to standard library json or other parsers under typical workloads
Memory overhead of string caching modes relative to parsing speed gains
Compatibility with GraalPy (listed in classifiers) and real-world usage stability

fast json parserjson parsing byteshigh performance jsonpartial json parsingjson to python objectlightweight json decoderjson parser no dependencies