Is there a size limit on JSON input?

The editor handles JSON up to approximately 10 MB comfortably. Larger files may be slow to render in the tree view.

Can I validate JSON Schema?

JSON Schema validation (draft-07 and draft-2019-09) is on the roadmap and coming soon.

Does it support JSON5 or JSONC?

JSON5 and JSONC (JSON with comments) parsing support is planned.

Can I share my formatted JSON with others?

Yes, use the Share button to generate a URL-encoded link. Note that the JSON is encoded in the URL, so very large documents may produce very long URLs.

Is my data kept private?

All formatting and validation happens locally in your browser. No data is sent anywhere.

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🌐 Runs in Browser⏱ Est. Instant

Formateur JSON

Formatez, validez et explorez JSON avec un puissant éditeur dans le navigateur

Try It Now — Free

What is Formateur JSON?

Instantly format, validate, minify, and explore JSON data. Highlights syntax errors, supports JSONPath queries, tree view, and diff comparison. Perfect for developers working with APIs.

Key Features

Instant format (pretty-print) and minify

Real-time syntax error detection with line numbers

Interactive tree view for nested data exploration

JSONPath query support for extracting values

JSON diff comparison between two documents

Convert JSON to YAML, CSV, and TypeScript types

Share via URL-encoded link

Dark-themed Monaco editor

How It Works

Paste or Type JSON

Paste your JSON into the editor or type it directly. The editor validates as you type.

Format or Minify

Click Format to pretty-print with configurable indentation, or Minify to compact it.

Explore

Switch to the tree view to navigate nested objects and arrays visually.

Export

Copy the result, download as a file, or share via a URL.

Who Is This For?

▸Developers debugging API responses
▸Backend engineers reviewing configuration files
▸QA teams validating JSON test fixtures
▸Data engineers exploring nested JSON datasets

Why Use Formateur JSON?

Unlike cloud-based alternatives that upload your files to remote servers, Formateur JSON runs entirely in your browser. Your data stays private. No account, no subscription, no upload limits — just instant results. Built with cutting-edge web technologies including WebAssembly and WebGL for near-native performance.

Technical Details

The editor is powered by Monaco Editor (the engine behind VS Code) running via CDN. JSON parsing uses the native browser JSON.parse() with a custom error-recovery layer for better error messages. Tree rendering uses a virtual DOM for performance with large documents.