In the Wild

Parsers

• jju -- A set of utilities to work with JSON / JSON5 documents
• golden-fleece -- Parse and manipulate JSON5 strings
• ObjFW -- A general purpose Objective-C framework which includes a parser with complete JSON5 support (JSON5 0.2 as of 28.01.2013)
• JSON5::Tiny -- A JSON5 parser and emitter for Perl 6
• json5_parser -- An enhancement of the JSON Spirit C++ parser to understand json5
• json5cpp -- A port of the reference implementation to C++
• ⎕JSON -- A to/from JSON5 converter is a core part of Dyalog APL
• https://pypi.org/project/json5/ -- An implementation for Python
• https://pypi.org/project/pyjson5/ -- A speed-optimized implementation for Python
• https://pypi.org/project/json-five/ -- An alternative implementation for Python
• https://github.com/yosuke-furukawa/json5 -- An implementation for Go
• https://github.com/bartoszkopinski/json5 -- An implementation for Ruby
• https://github.com/taichi-ishitani/rb_json5 -- An implementation for Ruby
• https://github.com/colinodell/json5 -- An implementation for PHP
• https://github.com/callum-oakley/json5-rs -- An implementation for Rust
• https://github.com/brimworks/json5.java -- An implementation for Java
• https://github.com/anjohnson/yajl/tree/json5 -- A version of the YAJL JSON parser and generator (written in C) that has been modified to support JSON5.
• https://github.com/Synt4xErr0r4/json5 -- An implementation for Java (similar to JSON-Java)

Libraries

• Babel uses JSON5 for its .babelrc config file, as of v5.8.20.
• Dyalog APL uses JSON5 for its .dcfg config files, as of v18.0
• Next.js uses JSON5 for some configuration files? Code
• JupyterLab uses JSON5 for its settings as of v1.0.0
• anymarkup can read JSON5.
• i18next's sync-fs-backend and node-fs-backend can both read JSON5.
• json5format is a Rust-based API plus sample command line tool (formatjson5) for reformatting JSON5 documents into a customizable, consistent style (notably, preserving data representation/precision and contextual comments).
• Apple has added JSON5 related reading options to their Swift and Objective-C JSON APIs for iOS 15+ Beta and macOS 12+ Beta.
• pnpm supports package.json5.

Apps

• Chromium uses JSON5 for internal configs, e.g. runtime_enabled_features.json5.
• Craft elaborately sequenced animation timelines using ProStyle. Write your stories in a declarative JSON5 syntax and ProStyle will generate the web content and scripts that animate it. (examples)
• A web-based JSON-to-CSV converter. The application is open source, and conversion is performed in the browser and data is never uploaded to a server.
• WebStorm natively supports JSON5.

Other

• Vim Syntax Support: json5.vim