How to format and validate JSON in 3 easy steps
- 1
Paste your JSON
Copy the JSON string from your API response, log, or config file and paste it into the editor.
- 2
Click Format or Minify
Format pretty-prints with 2-space indentation. Minify collapses the JSON into a single compact line.
- 3
Copy or download the result
Validation errors are shown instantly with line and column. Copy the output or download it as a .json file.
Why use the json formatter & validator tool from Super Utility Hub?
The JSON formatter makes messy API responses and config files readable in a single click. Paste any JSON, hit format, and it's instantly pretty-printed with proper indentation — or minified when you need the smallest possible payload.
It's also a strict validator. If your JSON is malformed, the tool pinpoints the exact line and column with a clear explanation of what's wrong, which is a lifesaver when debugging API payloads, webhook bodies, or exported data.
Everything happens locally in your browser — your data never leaves your device. Paste, format, copy, done. Free and unlimited.
- Processes everything in your browser — no upload servers involved
- Free forever with unlimited uses
- Works on Windows, macOS, Linux, Android and iOS
- No watermark or branding on your output, ever
Frequently asked questions
What does the validator catch?
Missing commas, unmatched braces or brackets, trailing commas, duplicate keys, and invalid values. Errors are reported with the exact line and column.
Is my JSON sent to a server?
No. Formatting and validation run entirely in your browser, so sensitive payloads and private config files never leave your device.
Can I use it for JSON with comments?
Strict JSON doesn't allow comments. JSONC or JSON5 files (VS Code settings, tsconfig comments) will be flagged — remove the comments first.
Does it handle large JSON files?
Yes, up to several megabytes comfortably. Extremely large files may need a moment for the indentation pass, which also runs locally.