Free Online JSON Formatter & Validator

Paste your JSON into the editor and click Format. The tool parses it and rewrites it with 2 spaces per level and one value per line, in the same editor. Click Copy to take the result, or Minify to turn it back into one line.

Format adds line breaks and 2-space indents so people can read the JSON. Minify removes every space and line break outside strings, which gives the smallest text for an API call or a config value. Both are built from the same parsed data.

The usual causes are a trailing comma, single quotes, keys without quotes, comments, or values like NaN and undefined. JSON allows none of these. The status bar shows the browser's message for the first problem and cuts long ones short; hover to read it all. Chrome and Edge include the line and column.

Paste it into the editor. The JSON validator checks the text again after each change and shows a green Valid JSON label or a red error message. It checks syntax only; it does not test your data against a JSON Schema.

No. Format always uses 2 spaces, and there is no tab, 4-space or sort option. Keys stay in their original order, except keys that are whole numbers, such as "2" or "10", which JavaScript moves to the top of their object.

Usually only the spacing changes. Because Format rebuilds the JSON from parsed data, whole numbers over 9,007,199,254,740,991 lose their last digits, 1.0 becomes 1, \u escapes become plain characters and a repeated key keeps its last value. Store long IDs as strings to keep them exact.

No. It accepts strict JSON only, so comments, trailing commas and unquoted keys are errors. A JSON Lines file fails at line 2 because it holds several values. Format one line at a time, or wrap the lines in [ ] with commas between them.

The editor stores your JSON in the page address after #data=, encoded as Base64, and updates it about half a second after you stop typing. Share Link copies that address. The part after # is not sent to our server when the link opens, but anyone holding the link can read the JSON.

The tool sets no limit. In a Node test of the same code, 6 MB of JSON was checked in 44 ms and formatted in 42 ms. Drawing very long text in the editor takes longer, and share links grow to about 3.5 times the JSON, so large files make huge links.

Your JSON is checked and formatted on your device and is not sent to us. The editor does copy it into the page address, which your browser keeps in its history, so click Clear when you finish with secrets. Analytics record clicks like Format and Copy, the time taken and a size range, never the JSON.