Is my JSON sent to a server?

JSON Formatter & Validator

Popular Runs in Your Browser

Format unreadable JSON into clean, indented structures. Features real-time syntax validation, exact error line and column detection, 2-space or 4-space formatting, and minification.

Browser-based: this tool works on your device and does not send your input to an Alona Tool server. See the Privacy Policy for details.

Fast Processing

Loading JSON Formatter & Validator… This tool is an interactive page and needs JavaScript enabled in your browser.

Example Usage & Test Cases

Minified payload

Input Scenario:

{"user":"alex","id":101,"roles":["admin","editor"]}

Generated Result:

Beautifully indented JSON with collapsible syntax highlighting

How It Works

Parses raw strings through the browser's native JSON parser with detailed syntax error extraction.

Frequently Asked Questions

Never! Your sensitive API payloads, tokens, and database dumps remain entirely inside your browser.

Good to Know

Common uses

Making API responses readable
Finding the exact spot of a syntax error

Limitations and notes

Common JSON errors: trailing commas, single quotes instead of double quotes, unquoted keys and comments.
Validation checks syntax only, not whether the data matches the structure an API expects.