JSON Formatter and Validator
Format, validate, minify and explore JSON with exact error positions. Runs entirely in your browser.
Runs in your browser. Your input is processed on your device and is not uploaded to our server.
How to use the JSON Formatter and Validator
- Paste JSON or open a .json file.
- Click Format, Minify or Sort keys. Errors are reported with the line and column.
- Copy or download the result, or browse it in the tree view.
The validator uses your browser’s strict JSON parser (RFC 8259), so anything it accepts is valid JSON. When parsing fails, the tool points to the line and column and explains common causes such as trailing commas, single quotes and unquoted keys. Large numbers beyond JavaScript’s safe integer range are flagged because they may lose precision when parsed.
Your data never leaves your device, which makes the tool safe for API responses that contain private data. Still, avoid pasting live secrets into any website.
Frequently asked questions
Why is my JSON invalid when it works in JavaScript?
JavaScript object literals allow single quotes, unquoted keys, comments and trailing commas. JSON does not.
Is there a size limit?
Only your device’s memory. Files of several megabytes format in a moment on most computers.