Online JSON Formatter & Validator

100% In-Browser & Private

Format, prettify, and validate JSON data online with instant syntax validation and clean indentation.

About JSON Formatter & Validator

JSON (JavaScript Object Notation) is the de facto data exchange format for modern web APIs. When receiving minified or compressed JSON from API responses, human debugging can be challenging. This online JSON Formatter cleans up unformatted JSON strings into structured, indented, human-readable code while highlighting syntax errors in real time.

Key Features & Capabilities

Beautify unformatted or minified JSON with standard indentation
Instant syntax validation with error notification for invalid JSON
Minify and minify-to-prettify conversion
100% client-side execution — safe for sensitive API payloads, tokens, and PII

How to Use This Tool

  1. 1

    Paste JSON

    Paste raw, minified, or unformatted JSON text into the Input area.

  2. 2

    Review formatted output

    The formatted, properly-indented JSON appears instantly in the Output area.

  3. 3

    Copy or refine

    Click the copy icon on the top right of the formatted textarea to copy the clean JSON.

Frequently Asked Questions

Why does my JSON show as "Invalid JSON"?

Common JSON syntax errors include trailing commas after the last array/object element, single quotes instead of double quotes around keys and strings, or unquoted property names.

Is there a file size limit for JSON formatting?

Because processing occurs in your browser memory, it can comfortably handle multi-megabyte JSON payloads without hitting server timeouts.

Client-Side Security Guarantee: All operations are processed locally in your browser sandbox using web standards. We never record, send, or store your code, data payloads, or tokens on any server.