JSON Formatter & Beautifier

Production-grade JSON workspace with Monaco syntax highlighting, validate-with-line/column errors, beautify and minify, indentation and sort-key options, upload/download, in-editor search, statistics, optional tree view, history, and Web Worker processing for large files. Formatting and validation run in your browser — JSON is not uploaded unless you explicitly save history while signed in.

How to Use the JSON Formatter & Beautifier

Paste or upload JSON, choose formatting options, run Beautify, Minify, or Validate, then copy or download the result. Errors show line and column in the Monaco editor.

  1. Paste JSON into the input editor or upload a .json / .txt file.
  2. Set indentation (2 spaces, 4 spaces, or tabs) and optional Sort Keys.
  3. Click Beautify to pretty-print, Minify to compress, or Validate to check syntax only.
  4. Review errors with line/column markers, or read statistics and tree view when available.
  5. Copy output or use Download Pretty / Download Minified from the toolbar.
  6. Use History to reload a prior run, or Clear to reset the workspace.

Beautify vs minify vs validate

  • Beautify — readable multi-line JSON with your chosen indent.
  • Minify — smallest whitespace-safe representation.
  • Validate — syntax check only; formatting unchanged.

Large files and performance

Large inputs are processed in a Web Worker so Monaco stays responsive. Extremely huge documents may still hit browser memory limits.

Common mistakes

  • Trailing commas after the last property (invalid in standard JSON).
  • Single-quoted strings — JSON requires double quotes.
  • Minifying before fixing validation errors.

Privacy

Core format/validate runs in your browser. History and favorites may sync only when you are signed in and explicitly save — not by default.

Limitations

Standard JSON only — no JSON5 comments or trailing commas accepted. Compare Mode and server-side storage are not part of the default workflow.

FAQ

What is the difference between Format and Minify?

Format (Beautify) adds indentation and line breaks for readability. Minify removes unnecessary whitespace to reduce payload size for APIs and storage.

Does my JSON leave the browser?

Formatting and validation run locally (Web Worker for large files). ToolsLibrary does not upload your JSON unless you explicitly save history while signed in.

How do I fix “Unexpected token” errors?

Usually a missing comma, trailing comma, single quotes instead of double quotes, or unmatched braces. The validator shows line and column in Monaco.

What indentation options are supported?

Choose 2 spaces, 4 spaces, or tabs in formatting options. Preferences apply to Beautify output.

Can I sort object keys alphabetically?

Yes. Enable Sort Keys to produce stable, diff-friendly JSON before you copy or download.

How large a JSON file can I process?

The editor targets files up to about 20 MB using a Web Worker so the UI stays responsive. Very large documents may still be limited by browser memory.

Can I upload and download files?

Yes. Upload .json or .txt via the file picker or drag-and-drop. After a successful run, download pretty or minified output from the toolbar.

What statistics does the tool show?

Characters, words, lines, objects, arrays, properties, depth, file size, and formatting time when available.

Can I validate without changing formatting?

Yes. Run Validate to get success or a precise error with line/column without beautifying or minifying first.

Does it support Unicode and emoji?

Yes. JSON strings are UTF-8 capable — you can format and validate multilingual content including RTL scripts and emoji.