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JSON Formatter & Validator

Input
Output

How to use

Paste or type your JSON into the input area. Pastefix instantly formats and validates it — no button click needed. If your JSON has syntax errors, the tool pinpoints exactly where the problem is, showing the line and column number. Toggle between Beautify and Minify modes using the buttons in the toolbar. Click "Explain with AI" for a detailed breakdown of your data structure.

What this tool does

Pastefix's JSON Formatter beautifies minified JSON, validates syntax, and uses AI to explain complex data structures in plain English. It detects the data type (object or array), counts keys, measures nesting depth, and calculates the payload size — all instantly in your browser.

Common use cases

  • Debugging API responses from REST and GraphQL endpoints
  • Validating configuration files (package.json, tsconfig.json) before deployment
  • Understanding deeply nested JSON structures from third-party APIs
  • Formatting minified JSON for code reviews and documentation
  • Finding syntax errors in hand-written JSON payloads

Frequently Asked Questions

Is my JSON data secure?

Yes. JSON formatting and validation happen entirely in your browser. Your data never leaves your device unless you click "Explain with AI," which sends it to a server for analysis.

What is the maximum input size?

Pastefix handles JSON up to 10,000 characters. This covers the vast majority of API responses and configuration files.

Do I need to create an account?

No. All tools work instantly with zero signup, no cookies, and no tracking beyond anonymous analytics.

Can I minify JSON too?

Yes. Use the Beautify/Minify toggle in the toolbar. Minify strips all whitespace to produce the most compact JSON possible — useful for reducing payload size.