JSON Formatter & Validator
Beautify, minify, and validate JSON instantly.
About JSON Formatter
Paste raw or minified JSON and instantly beautify it with proper indentation and colour-coded structure. The validator highlights exact syntax errors with line numbers so you can fix them fast. Also minifies JSON to the smallest possible size for APIs and storage.
Use Cases
Debugging API responses, prettifying minified JSON configs, validating JSON before committing, inspecting webhook payloads, formatting JSON in documentation.
How It Works
Uses the native JavaScript JSON.parse() to validate and parse input, then JSON.stringify() with configurable indent spacing to reformat it — all running locally in your browser.
FAQs
What does the validator catch?
All JSON syntax errors: trailing commas, unquoted keys, wrong quote types, mismatched brackets, and invalid values like undefined.
Is there a size limit?
No hard limit — the tool runs in your browser so very large JSON (10 MB+) may be slow depending on your device.
Can I choose the indentation?
Yes. Switch between 2-space, 4-space, or tab indentation.