Free Online JSON Validator — Validate JSON Instantly

Paste your JSON to validate it with detailed error reporting. See file size, key count, nesting depth, and value type statistics.

About JSON Validator

This free online JSON validator checks your JSON data for syntax errors and provides detailed feedback including the exact line number and column where errors occur. All processing happens client-side in your browser — your data never leaves your device.

Features

Validate JSON with detailed error messages and line numbers
File size calculation in bytes, KB, or MB
Total key count across all nested objects
Maximum nesting depth analysis
Value type breakdown (strings, numbers, booleans, nulls, objects, arrays)

When to Use a JSON Validator

JSON validation is essential when working with APIs, configuration files, or data interchange. Common JSON errors include missing commas, unmatched brackets, trailing commas, and single quotes instead of double quotes. This tool catches all of these instantly.