CodePersia

JSON Formatter Online — Format, Beautify & Validate JSON

Tool processing happens entirely in your browser. Your input is never sent to our servers.

What is JSON Formatting?

JSON formatting (also called "pretty printing") transforms compact JSON into a readable, indented structure. When JSON is transmitted over networks or stored in files, whitespace is typically stripped to save bytes. While efficient for machines, this makes the data nearly impossible for humans to read.

A JSON formatter parses the JSON string, validates its structure, and rebuilds it with consistent indentation and line breaks. This makes it easy to see the hierarchy of objects and arrays, spot missing values, and understand the overall data shape.

When to format JSON: debugging API responses, reviewing configuration files, inspecting database documents, preparing data for documentation, or any time you need to understand a JSON payload quickly.

Indentation styles: The most common choices are 2 spaces (popular in JavaScript/TypeScript projects), 4 spaces (common in Python ecosystems), and tabs (preferred by some teams for accessibility reasons, since tab width is configurable).

Once you have formatted your JSON, you might want to validate it for errors, minify it for production, or encode it as Base64 for embedding in other formats.

How to Use This JSON Formatter

  1. Paste or type your input in the editor above
  2. Click the action button or the tool will process automatically
  3. View the result in the output panel
  4. Copy the result with one click using the Copy button

Frequently Asked Questions

Yes, completely free with no limits. Your data never leaves your browser — all processing happens client-side.

It catches all syntax errors including missing commas, unclosed brackets, trailing commas, single quotes instead of double quotes, and unescaped special characters. Each error includes a line number and descriptive message.

Standard JSON does not support comments. If your JSON contains comments, the formatter will report a syntax error at the comment location. Consider using JSONC (JSON with Comments) tools for configuration files.

No artificial limit. The tool handles any size your browser can hold in memory. For files over 200KB, syntax highlighting is disabled for performance. Files over 1MB show a processing warning.