Format, validate & beautify JSON.
Paste messy JSON and get it formatted, validated and syntax-highlighted instantly. Tree view, JSON stats, minify mode, precise error detection. 100% private — runs in your browser.
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HOW IT WORKS
Format JSON in three steps
Paste your JSON
Paste any JSON — from an API response, config file, database export or log. Minified, nested, or malformed — it handles everything.
Choose a mode
Format to beautify with syntax highlighting. Switch to Tree View to explore nested data. Minify to compress for production.
Copy the output
One click copies the formatted JSON. The stats bar shows key count, depth, objects and arrays at a glance.
FEATURES
Built for developers
Syntax highlighting
Keys, strings, numbers, booleans and null values are colour-coded. Instantly distinguish data types at a glance in the text view.
Interactive tree view
Switch to tree view to explore nested objects and arrays. Collapse and expand nodes to navigate complex JSON structures.
JSON stats panel
Instantly see key count, object count, array count, nesting depth and output size — no digging through the JSON manually.
Precise error messages
When JSON is invalid, the error shows the exact position — line number and character — so you can fix it in seconds, not minutes.
Minify for production
Strip all whitespace to produce the smallest valid JSON string — reduces payload size for APIs, config files and localStorage.
100% private
All processing happens in your browser. No data is sent to any server. Safe to paste API tokens, credentials and PII.
Why JSON formatting matters — and the mistakes every developer makes
JSON (JavaScript Object Notation) is the dominant data interchange format for APIs, configuration files, and databases. When working with raw API responses or minified data, formatting makes the difference between spending 30 seconds or 30 minutes understanding the structure of a response.
The most common JSON validation errors are deceptively easy to introduce: trailing commas after the last item in an array or object are valid in JavaScript and TypeScript but are explicitly forbidden in the JSON specification (RFC 8259). Comments — both // and /* */ — are not valid JSON, despite appearing in tsconfig.json and other JSONC files.
For production use, always minify your JSON to reduce payload size. A formatted API response adds whitespace bytes that compound at scale — a 10KB formatted response might be 6KB minified, saving 40% in transfer. For debugging complex nested structures, use the tree view — it collapses nodes so you can navigate hundreds of keys without scrolling through thousands of lines.
FAQ
Frequently asked questions
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