JSON Formatter

JSON Formatter is a free online tool for formatting, validating, and beautifying JSON (JavaScript Object Notation) data. JSON is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate.

Our JSON Formatter helps you transform minified or poorly formatted JSON into clean, readable text with 2, 4 or 8 space indentation. When the JSON will not parse, it shows the parser error message instead of an output, so you can find and fix the problem.

Whether you're a developer debugging API responses, a data analyst working with JSON files, or learning about JSON structure, the tool gives you Format, Minify and Validate buttons over a plain input and output pane. Processing happens client-side, so your JSON is never uploaded; Format and Minify log a usage record that holds only the input length.

Here is a worked example of the JSON beautifier online. Paste the minified `{"user":{"id":7,"tags":["x","y"]}}`, leave Indent on 2 spaces and press Format: the output has nine lines, with `"user"` on its own line and each tag indented six spaces. Press Minify and the same input comes back as one line. Used as a JSON formatter checker, press Validate on `{"a":1,}` and, in a Chrome-based browser, the error reads "Expected double-quoted property name in JSON at position 7 (line 1 column 8)", which points at the trailing comma.

Most JSON that fails to parse fails for one of four reasons, and the first three raise an error. Trailing commas are the commonest: valid in JavaScript, invalid in JSON, and the reason a config copied out of an editor so often will not load. Comments are the second, since JSON has none at all, which is why JSONC and JSON5 exist as separate formats. Single quotes are the third; JSON requires double quotes on both keys and strings. The fourth is subtler and does not raise an error. Numbers are IEEE 754 doubles, so any integer above 9007199254740991 loses precision silently: a 64-bit database id pasted into JSON can come back as a different number. Ids that large belong in strings. Duplicate keys are not an error either, and the last one wins.