What is a .json file?

You opened a file and it's full of curly braces, square brackets, and key-value pairs. That's JSON — the format that web APIs speak. Every time your browser fetches data from a server — a weather forecast, a social media feed, search results — the response almost certainly arrives as JSON.

JSON stands for JavaScript Object Notation, but calling it a JavaScript format undersells its reach. It's language-independent, human-readable, and so minimal the entire specification fits on a business card: curly braces for objects, square brackets for arrays, colons between keys and values, commas between entries. Douglas Crockford didn't invent it so much as discover it — the syntax was already inside JavaScript, waiting for someone to write down the rules. It replaced XML for most web data exchange because it's less verbose and easier to parse.

Any text editor opens JSON. VS Code and most code editors provide syntax highlighting and formatting. Firefox renders JSON in a navigable tree view. For converting JSON to CSV or vice versa, fwip handles it in the browser. If you're debugging an API response or editing a configuration file, JSON is what you're looking at.