JSON Formatter
Format, validate and minify JSON online.
🔒 100% browser-based — your data never leaves your device.
About this tool
Paste raw JSON and format it into readable, properly indented output, or minify it into a single compact line for transmission. If the JSON is invalid, the tool shows the parser error message with the position, which makes it easy to find missing commas, unclosed brackets or stray trailing commas.
Everything runs locally in your browser, so API responses, config files and payloads containing sensitive data never leave your machine.
Frequently asked questions
Why is my JSON invalid?
The most common causes are trailing commas after the last item, single quotes instead of double quotes, and unquoted property names. JSON requires double quotes and forbids trailing commas.
What is the difference between formatting and minifying?
Formatting adds line breaks and indentation for humans; minifying removes all unnecessary whitespace to make the payload as small as possible for machines.
Is my JSON data uploaded?
No. Parsing and formatting use your browser’s built-in JSON engine. Nothing is transmitted.