A developer's guide to JSON — formatting, validation, and common mistakes

JSON is everywhere. It's the format your API returns data in. It's your config files, your package.json, your database exports, your webhook payloads. If you write code that talks to anything else, you're working with JSON every single day. And yet it trips developers up constantly — not because it's complicated, but because it's unforgiving. One missing comma, one extra bracket, one set of single quotes instead of double, and the whole thing breaks. This guide covers what you actually need to know. What JSON is and why it matters JSON stands for JavaScript Object Notation. It was designed to be lightweight, human-readable, and easy for machines to parse. It succeeded on all three counts, which is why it became the default data format for APIs and web services. A JSON object looks like this: { "name": "DevCrate", "tools": 12, "private": true, "url": "https://devcrate.net" } Keys are always strings wrapped in double quotes. Values can be strings, numbers, booleans, arrays, objects, or n