Validate

Detect errors with line numbers.

Format

Pretty print with indentation.

Minify

Compress to single line.

Private

100% browser-based. No uploads.

Our free JSON formatter helps developers validate, format, and minify JSON data instantly in your browser with zero server uploads.

Paste JSON above to validate automatically.
Validation runs automatically as you type. All processing happens in your browser.
0
Total Keys
0
Objects
0
Arrays
0
Max Depth
JSON Details
Status Empty
Characters 0
Lines 0
Size 0 B

Free Online JSON Formatter and Validator

Welcome to the most secure and developer-friendly JSON Formatter and Validator. Whether you are debugging API responses, cleaning up configuration files, or validating data structures, our tool provides instant formatting, validation, and analysis entirely in your browser.

Why use this JSON tool?

Unlike online tools that upload your data to servers, WebNestix processes everything 100% client-side. Your JSON never leaves your browser, ensuring complete privacy and security. Key features include:

  • Real-Time Validation: Instantly detect syntax errors with precise line and column numbers.
  • Pretty Print Formatting: Transform minified JSON into readable, indented format with one click.
  • Minification: Compress JSON by removing all unnecessary whitespace for production use.
  • Structure Analysis: See counts for keys, objects, arrays, and maximum nesting depth.

How to use

  1. Paste your JSON data into the editor above.
  2. The tool automatically validates your JSON and shows any errors.
  3. Click "Format" to pretty-print or "Minify" to compress.
  4. Use "Copy" to copy the result to your clipboard.

Common JSON use cases

JSON (JavaScript Object Notation) is the standard data format for APIs, configuration files, and data storage. Developers frequently need to validate JSON from REST APIs, format configuration files for readability, minify JSON for network efficiency, and debug malformed data structures. Our tool handles all these tasks instantly without any software installation.

Privacy and Security

Your data stays on your device. We use no server-side processing, no cookies for tracking, and no data storage. This makes our tool ideal for sensitive data like API keys, user records, and proprietary configurations. All JavaScript runs locally in your browser.

Frequently Asked Questions

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It is commonly used for API responses and configuration files.

Is my JSON data secure with this tool?

Yes, absolutely. All processing happens entirely in your browser using JavaScript. Your JSON data is never sent to any server, making it completely private and secure.

What causes "Unexpected token" errors?

This error typically occurs due to trailing commas, missing quotes around keys, single quotes instead of double quotes, or unescaped special characters. Our validator shows the exact line and position of the error.

Can I format large JSON files?

Yes, the tool can handle large JSON files. However, very large files (several megabytes) may take a moment to process depending on your browser and device performance.

What is the difference between Format and Minify?

Format (pretty print) adds indentation and line breaks for readability. Minify removes all unnecessary whitespace to create the smallest possible file size, ideal for production use.