📖 What is JSON Validator?
A JSON Validator checks whether a JSON string conforms to the JSON specification (RFC 8259). It identifies syntax errors like missing brackets, unclosed strings, trailing commas, and invalid characters — giving you the exact position of each error.
💡 Example
Input
{"name":"Alice","age":30,"active":true}
Output
✓ Valid JSON
Type: object
Keys: 3
Size: 38 bytes
🛠️ Common Use Cases
- Validating API request/response bodies before deployment
- Debugging parse errors in configuration files
- Checking user-submitted JSON data
- Verifying JSON exported from databases
- Testing webhook payloads
❓ Frequently Asked Questions
What makes JSON invalid? ▾
Common errors include: trailing commas after the last item, single quotes instead of double quotes, unquoted keys, missing colons, extra closing brackets, and undefined values.
What is the difference between JSON and JavaScript objects? ▾
JavaScript objects allow unquoted keys, single quotes, trailing commas and comments. JSON is a strict subset that requires double-quoted keys, no trailing commas, and no comments.
Does the validator fix errors automatically? ▾
No — it identifies and reports errors but doesn't auto-fix them, as the correct fix depends on your intent. Use the JSON Formatter to beautify valid JSON.
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Your data stays private. All processing happens entirely in your browser using JavaScript. Nothing is ever sent to our servers. You can even use this tool offline after the page loads.