JSON Formatter & Validator

Formatting JSON is really two jobs: parsing and printing. The parser reads your text and either produces a JavaScript value or fails. If it fails, the failure is the useful output — a formatter that just says "invalid JSON" has wasted your time. This tool surfaces the parser's own diagnosis and, where the browser gives a character offset, converts it to a line and column so you can jump straight to the problem instead of counting characters.

Once parsed, printing is a choice about whitespace. Beautify re-emits the document with two or four spaces (or tabs) of indentation per level, which is what you want while reading or debugging. Minify emits it with none, which is what you want on the wire — for a large API payload the saving is routinely 20–30% before compression even starts. Sort keys re-emits the document with every object's keys in alphabetical order, recursively. That one is underrated: two JSON documents that are semantically identical but written in different key orders look completely different in a diff, and sorting both first makes the real differences visible.

Worth knowing about what JSON does not allow, since these are the errors people hit most: comments are not permitted, trailing commas after the last element are not permitted, keys must be wrapped in double quotes, and single quotes are never valid for either keys or strings. JavaScript object literals allow all of those, which is exactly why code pasted out of an editor so often fails to parse here.

Everything runs locally in your browser using its native JSON parser — the same one your code uses. There is no upload, no logging and no size limit beyond your device's memory, so pasting a production API response, an access token payload or a customer record carries no more risk than opening the file in a text editor.