JSON Validator & Formatter
Paste your JSON below to see syntax errors instantly and pretty-print it with 2-space indentation in one click. Everything runs in your browser — nothing is sent to a server.
Advertisement
How to use it
Paste your JSON into the box and click Validate & Format. If the JSON is invalid, you'll see exactly which character caused the error. Use it to make minified API responses readable, or strip whitespace with Minify.
Frequently Asked Questions
How do I validate large JSON files?
Just copy the file's contents into the box. Everything happens in your browser with no upload to a server, so it's safe for sensitive data too.
Can I use comments inside JSON?
No, standard JSON doesn't support comments. Files with comments (JSONC) need to have them stripped first.
Why does a trailing comma cause an error?
The JSON spec forbids a comma after the last element — unlike JavaScript object literals, JSON doesn't allow it.