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Json Formatter

JSON is the lingua franca of web APIs, configuration files and NoSQL databases — but minified or hand-edited JSON is a nightmare to read. Our free JSON formatter takes a single-line blob of JSON and pretty-prints it with proper indentation, validates that the syntax is correct, and reports the exact line and column of any error. You can also minify JSON in the other direction.

Input JSON

Output

Valid JSON Invalid

Formatted JSON will appear here

Keys

Depth

Raw Size

Root Type

JSON Formatting Tips

Use 2-space indentation for readable JSON in APIs and config files.
Minified JSON is faster to transmit over networks and APIs.
JSON keys must be strings in double quotes — single quotes are invalid.
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About the JSON Formatter & Validator

JSON is the lingua franca of web APIs, configuration files and NoSQL databases — but minified or hand-edited JSON is a nightmare to read. Our free JSON formatter takes a single-line blob of JSON and pretty-prints it with proper indentation, validates that the syntax is correct, and reports the exact line and column of any error. You can also minify JSON in the other direction.

How to use it

  1. Paste or type your JSON into the editor area.
  2. Click Format to pretty-print with proper indentation and line breaks.
  3. Click Validate to check syntax — errors show the exact line and column.
  4. Click Minify to compress JSON into a single line for production use.
  5. Copy the formatted or minified output with the copy button.

Formula & methodology

JSON parsing follows the ECMA-404 specification. Validation checks for: valid syntax, balanced brackets and braces, proper string escaping, correct number formatting, and no trailing commas.

Common use cases

  • Formatting minified API responses for debugging during development
  • Validating hand-edited configuration files before deployment
  • Preparing JSON payloads for API testing in Postman or curl
  • Minifying JSON to reduce payload size in production applications
  • Teaching JSON syntax to students learning web development

Frequently asked questions

The validator detects syntax errors including missing commas, unbalanced brackets, unescaped quotes, invalid number formats, trailing commas, and incorrect key-value separators. Each error is reported with the exact line and column number for quick fixing.
Yes, the tool runs entirely in your browser and can handle JSON files up to several megabytes. Processing happens client-side so there are no server upload limits. For extremely large files (10MB+), formatting may take a few seconds.
No. Everything runs in your browser using JavaScript. Your JSON data never leaves your device — no uploads, no logs, no server-side processing. This makes the tool safe for processing sensitive configuration files or API responses containing private data.

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