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Free Online JSON Formatter, Viewer & Validator

JSON Viewer Pro is a fast, privacy-first JSON workspace that runs entirely in your browser. Format, validate, minify, diff, and explore JSON in table and tree views — no uploads, no server processing, no account required.

Popular JSON Tools

JSON Viewer Pro is a free, browser-based JSON toolkit built for developers, QA engineers, and data analysts who work with JSON every day. Whether you need to format a minified API response, validate JSON syntax before deployment, inspect a deeply nested data structure, or review records in a table view, all the tools you need are available here — instantly and without any sign-up.

Unlike other online JSON tools, JSON Viewer Pro processes everything locally in your browser. Your JSON data is never uploaded to a server, never logged, and never shared. This makes it safe to use with sensitive data including API responses, database exports, and configuration files that may contain credentials or private information.

From the JSON formatter and validator to the diff tool, CSV converter, and privacy scanner, every feature is available offline after the first page load. JSON Viewer Pro works as a Progressive Web App, so you can add it to your home screen and use it anywhere — even without an internet connection.

Key Features

  • ✓ Browser-based — your JSON never leaves your device
  • ✓ No sign-up or login required — completely free
  • ✓ Fast JSON formatting and pretty printing
  • ✓ Real-time JSON syntax validation with line/column errors
  • ✓ JSON minification to reduce file size
  • ✓ Table and tree views for exploring JSON data
  • ✓ Side-by-side JSON diff — compare two documents
  • ✓ Convert JSON to CSV and YAML
  • ✓ Privacy scanner — detect secrets, tokens and PII

Common Use Cases

  • → Debug API responses from REST or GraphQL
  • → Format minified JSON from logs or terminals
  • → Validate JSON syntax before sending to an API
  • → Read deeply nested JSON structures visually in tree or table view
  • → Compare two JSON payloads side by side
  • → Convert JSON data to CSV for spreadsheets
  • → Detect and redact sensitive fields before sharing
  • → Explore unfamiliar JSON schemas quickly

Frequently Asked Questions

Is my JSON data private?

Yes. All processing happens entirely in your browser using JavaScript. Your JSON is never sent to any server, stored in a database, or shared with any third party.

Does JSON Viewer Pro work offline?

Yes. After the first load, JSON Viewer Pro works as a Progressive Web App (PWA) and is fully available offline. Core features like formatting, validation, tree view and diff all work without an internet connection.

Is it free to use?

Yes, completely free. No login, no account, no subscription required. All core JSON tools are available at no cost.

What JSON tools are available?

JSON Viewer Pro includes a formatter (pretty printer), validator, minifier, table view, tree viewer, diff tool, JSON-to-CSV converter, JSON-to-YAML converter, search, and a privacy/secret scanner.

JSON Tools

XML Tools

HTML Tools

JSON Viewer Pro — all processing runs locally in your browser. Your data is never sent to any server. Free to use, no account required.Privacy Policy·Contact

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