Paste your JSON and instantly know if it's valid — with precise error location, line numbers and type analysis.
Catch syntax errors before they reach production.
Errors show the exact line and column so you can fix them immediately.
Line numbers update as you type, making navigation through large JSON easy.
See key count, nesting depth, root type and character count at a glance.
Validation runs automatically as you type — no button clicks needed.
Type or paste your JSON text into the input area — any size or complexity.
The validator checks syntax and reports errors with line numbers and descriptions.
Use the error messages to correct your JSON, then validate again until it passes.
This free online json validator tool is designed to work entirely in your browser — no uploads, no waiting, no software installation needed. It's fast, private, and completely free to use without any account or subscription.
{"a":1,} is invalid JSON — trailing commas are not allowed, unlike JavaScript.
JSON requires double quotes for strings and keys. Single quotes are a common mistake.
Validation errors include line and column numbers — use them to jump directly to the problem.
Once validated, use our JSON Formatter to make your JSON human-readable.
JSON validation is essential for developers debugging API integrations, configuration files, and data pipelines where invalid JSON causes failures.