JSON Validator

Check whether your JSON is valid with instant, precise error reporting. Paste API responses, configuration files, or any JSON data to validate syntax and identify problems. Line-level error messages help you fix issues fast.

How It Works

  1. Open the JSON Validator on Toolyy.
  2. Paste your JSON into the editor.
  3. Click Validate to check syntax. Errors are highlighted with line numbers and descriptions.

Why Use Toolyy?

  • 100% Private — your files never leave your device. All processing runs locally in your browser.
  • No Account Required — no sign-up, no email, no login. Just open and use.
  • No File Size Limits — no artificial server caps. The only limit is your device’s memory.
  • Completely Free — no premium tiers, no watermarks, no per-file fees.

Frequently Asked Questions

What types of JSON errors does it detect?

Missing commas, extra commas, unquoted keys, mismatched brackets, invalid escape sequences, trailing commas, and all other syntax violations.

Can I validate large JSON files?

Yes. Since parsing happens in your browser, there's no server-side limit. Files up to several megabytes parse instantly.

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