JSON Formatter & Validator
Paste messy JSON and get it cleanly formatted, minified or validated — with helpful error messages when something's wrong.
What this tool does
JSON (JavaScript Object Notation) is the most common format for sending data between apps and APIs. When it's minified into one long line it's unreadable. This formatter parses your JSON, validates it, and re-prints it with clean indentation so you can actually read it — or minifies it to save bytes for production.
Reading error messages
If your JSON is invalid, the status bar shows the parser's error (such as an unexpected token or a missing comma) so you can find and fix the problem quickly. Common culprits are trailing commas, single quotes instead of double quotes, and unquoted keys.
Is my JSON sent to a server?
No. Parsing and formatting happen entirely in your browser using the native JSON engine. Nothing is uploaded.
Does it handle large files?
Yes, within your browser's memory limits — it comfortably handles typical API responses and config files.