---
id: json5
version: "0.15.0"
license: Files: Everything except for the benchmarks/*.json files. Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1.… (full text in the JSON record)
license_treatment: permissive
maintenance: active
---

# json5 — A Python implementation of the JSON5 data format.

License: permissive · Maintenance: active · Popularity: top 1,000 on PyPI

## Install

pip install json5
uv add json5
poetry add json5

## Description

# pyjson5

A Python implementation of the JSON5 data format.

[JSON5](https://json5.org) extends the
[JSON](http://www.json.org) data interchange format to make it
slightly more usable as a configuration language:

* JavaScript-style comments (both single and multi-line) are legal.

* Object keys may be unquoted if they are legal ECMAScript identifiers

* Objects and arrays may end with trailing commas.

* Strings can be single-quoted, and multi-line string literals are allowed.

There are a few other more minor extensions to JSON; see the above page for
the full details.

This project implements a reader and writer implementation for Python;
where possible, it mirrors the
[standard Python JSON API](https://docs.python.org/library/json.html)
package for ease of use.

There is one notable difference from the JSON api: the `load()` and
`loads()` methods support optionally checking for (and rejecting) duplicate
object keys; pass `allow_duplicate_keys=False` to do so (duplicates are
allowed by default).

This is an early release. It has been reasonably well-tested, but it is
**SLOW**. It can be 1000-6000x slower than the C-optimized JSON module,
and is 200x slower (or more) than...

## AI interpretation — verify before relying

Parses and serializes JSON5, a relaxed JSON format that allows comments, unquoted keys, trailing commas, and single-quoted strings for use as a configuration language.

Verdict: A well-maintained, permissively licensed JSON5 implementation suitable for parsing relaxed JSON in configuration workflows. Zero dependencies and broad Python version support make it easy to integrate. However, its documented performance limitation (200–6000× slower than json) means it should be reserved for configuration files and non-performance-critical use cases.

[View on SkillFed](https://skillfed.io/packages/json5) · [View on PyPI](https://pypi.org/project/json5/)