JSON Formatter & Validator
Minify and prettify JSON with real-time error checking
Input
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Output — Code
1
Notes
- Format / Minify — Prettify your JSON with proper indentation (2 or 4 spaces) or compress it into a single line for production use.
- Auto-fix — When your JSON is invalid, the tool detects if it can be repaired automatically. Fixes common issues like trailing commas, single quotes, and unquoted keys.
- Tree View — Switch to a collapsible tree view to explore large JSON structures. Expand and collapse nodes to focus on the data you need.
- Sort Keys — Alphabetically sort all keys (A-Z) at every nesting level. Useful for comparing two JSON payloads side by side.
- Upload / Download — Drag and drop a .json or .txt file onto the page, or use the Upload button. Export the result as a .json file with one click.
- All processing happens entirely in your browser. No data is sent to any server.
JSON Formatter & Validator
A free, fast, and private JSON formatter and validator that runs entirely in your browser. Paste or upload your JSON data to instantly format, minify, validate, and explore it — no server-side processing, no data collection, no sign-up required.
Why Format & Validate JSON?
- Improved Readability — Raw JSON from APIs and databases is often minified or unindented. Formatting makes nested structures easy to read and understand at a glance.
- Instant Error Detection — Catch syntax errors like missing brackets, extra commas, or invalid values before they cause runtime bugs in your application.
- Faster Debugging — Quickly identify the structure and values of complex JSON payloads returned from REST APIs, GraphQL endpoints, or configuration files.
- Data Preparation — Clean up and sort keys before storing JSON in databases, sending it to APIs, or committing it to version control.
- Development Efficiency — Auto-fix common mistakes, toggle between formatted and minified views, and export results — all without leaving your browser.
Common JSON Validation Errors
- Trailing Commas — A comma after the last item in an array or object is not valid JSON, though JavaScript allows it.
- Single Quotes — JSON requires double quotes for strings. Single quotes will cause a parse error.
- Unquoted Keys — All object keys in JSON must be wrapped in double quotes, unlike JavaScript object literals.
- Missing Brackets — Unclosed arrays
[]or objects{}are the most common structural errors. - Invalid Values — JSON only supports strings, numbers, booleans, null, objects, and arrays. Values like
undefinedorNaNare not valid.
Privacy & Security
Your JSON data never leaves your device. All formatting, validation, and transformation is performed client-side using JavaScript. We do not collect, store, or transmit any data you paste or upload — making this tool safe for sensitive configurations, API keys, and production data.