> For the complete documentation index, see [llms.txt](https://johnkazer.gitbook.io/core-web-dev-concepts/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://johnkazer.gitbook.io/core-web-dev-concepts/app/json.md).

# JSON

JSON is a critical concept. It is a file or object syntax definition, used by many apps to store data, generate configuration files, manage data within code and pass information between websites to/from a server