JSON Formatter & Validator

JSON (JavaScript Object Notation) is the lingua franca of modern APIs. Whether you're building a REST service, debugging a webhook, or reading a config file, JSON formatting is a daily task for every developer. A well-formatted JSON document is dramatically easier to read — nested structures become clear, typos become obvious, and sharing with teammates becomes productive.

What this tool does

Paste any JSON string — minified, broken across lines, or with inconsistent spacing — and click Format. The output is pretty-printed with 2-space indentation (configurable), sorted keys (optional), and inline syntax highlighting. Switch to Minify mode to strip all whitespace for production payloads. The validator runs on every keystroke and highlights the exact character position of syntax errors.

Common use cases

- Debugging API responses from Postman, Insomnia, or browser DevTools - Cleaning up config files (package.json, tsconfig.json, .prettierrc) - Preparing examples for documentation or Stack Overflow answers - Verifying webhook payloads from Stripe, GitHub, or any event source - Transforming single-line log output from production systems

Why browser-based?

Production JSON often contains sensitive data: auth tokens, PII, internal service names. A browser-based formatter processes everything locally in the JavaScript engine. Nothing is transmitted. Your data stays in your browser tab and is gone when you close it.

About JSON syntax

JSON has strict rules: keys must be double-quoted strings, trailing commas are not allowed, and the file must have a single root value (object or array). If you need to work with more lenient formats, JSON5 is a superset that allows comments, trailing commas, and unquoted keys — Utilix has a JSON5 tool on the roadmap.