Why use this JSON Formatter?
Smart Auto-Repair
Stop fighting syntax errors. If you paste a raw JavaScript object (single quotes, trailing commas, unquoted keys), our engine automatically repairs and converts it into strict valid JSON.
Developer Experience
Enjoy an IDE-like experience with dynamic line numbering, deep syntax highlighting, payload size analytics, and one-click JSON file downloads.
100% Private (No Logs)
Your API data never leaves your browser. Parsing, validation, and minification happen locally via JavaScript. Your payloads remain completely secure.
Frequently Asked Questions
Why does my JSON say "Syntax Error"?
Strict JSON requires double quotes (") around all keys and string values, and does not allow trailing commas (e.g. {"a": 1,}). Enable the Smart Repair checkbox and the tool will attempt to fix these automatically.
What is JSON Minification?
Minifying JSON strips all spaces, tabs, and line breaks to create the smallest possible payload. The payload size indicator above the input box shows exactly how many kilobytes you save before sending data to an API.