JSON is everywhere — APIs, config files, databases. If you work with data, you need to understand it. Here's the fastest possible introduction.
What JSON Looks Like
It's text that represents structured data using two building blocks: objects (key-value pairs in curly braces) and arrays (ordered lists in square brackets). That's the entire specification.
Rules
Keys must be strings in double quotes. Values can be: strings, numbers, true/false, null, arrays, or other objects. No trailing commas (the most common syntax error). No comments (unfortunately).
Common Uses
APIs: 90%+ of web APIs return JSON. Config files: package.json, tsconfig.json, .prettierrc. Databases: MongoDB stores JSON documents natively. Data exchange: simpler and lighter than XML.
Tools
Validate and format messy JSON with our JSON formatter. Convert spreadsheet data to JSON with CSV to JSON converter. Going the other direction? JSON to CSV flattens nested data into rows.