JSON Formatter & Validator

Format, validate, and beautify JSON data with syntax highlighting. Minify JSON for production use.

Runs in your browser · Data never leaves your device

What is a JSON Formatter & Validator?

A JSON Formatter (also called a JSON Beautifier or JSON Prettifier) takes minified or hard-to-read JSON data and reformats it with proper indentation and line breaks, making it easy for developers to read, debug, and share. JSON (JavaScript Object Notation) is the universal data exchange format used in REST APIs, configuration files, and web applications worldwide. When APIs return compact, single-line JSON to reduce bandwidth, developers need to quickly inspect its structure — this tool does that entirely in your browser, with zero data sent to any server. It also validates your JSON against the official RFC 8259 specification and highlights the exact location of any syntax errors.

How to use this tool

  1. Paste your raw or minified JSON into the Input JSON box on the left.
  2. Click Format to instantly pretty-print with indentation, or Minify to compress it.
  3. Choose your preferred indent size: 2 spaces, 4 spaces, or tab.
  4. Inspect the syntax-highlighted output in the right pane — keys, strings, numbers, and booleans are color-coded.
  5. Click Copy to copy the formatted result to your clipboard, or Clear to start over.

Common use cases

  • Inspecting API responses during backend or frontend development and debugging
  • Reading configuration files exported from databases, CMS platforms, or DevOps tools
  • Preparing JSON payloads for documentation, Postman collections, or code reviews
  • Validating that a JSON string is syntactically correct before parsing it in your code
  • Minifying JSON for production environments to reduce HTTP payload size
  • Teaching or learning JSON structure by seeing clearly indented, color-coded output

Frequently asked questions

Is my data safe when using this tool?
Yes — all formatting and validation happens entirely in your browser using JavaScript. Your JSON data is never transmitted to our servers or stored anywhere.
Does this tool validate JSON?
Yes. If the input is not valid JSON, the tool immediately shows an error message identifying the type and approximate location of the syntax problem, such as a missing comma, unclosed bracket, or invalid value.
What is the maximum JSON size this tool can handle?
There is no hard limit enforced by this tool. However, very large JSON files (over 10 MB) may slow down your browser due to DOM rendering constraints. For files that large, consider using a dedicated desktop JSON editor.
Can I format JSON with comments (JSON5 or JSONC)?
Standard JSON does not support comments. This tool follows the strict JSON specification (RFC 8259). If your file uses JSON5 or JSONC format (with // or /* */ comments), you need to strip the comments before pasting.
What is the difference between formatting and minifying JSON?
Formatting (or beautifying) adds whitespace — newlines and indentation — to make JSON human-readable. Minifying removes all unnecessary whitespace to produce the smallest possible JSON string, which reduces file size for network transmission.