What does the JSON validator check?
Our JSON validator checks your input against the full JSON specification (RFC 8259). It catches common issues developers encounter:
- Missing or extra commas
- Unquoted or single-quoted keys
- Trailing commas (not valid in JSON)
- Unclosed brackets or braces
- Invalid escape sequences in strings
- Comments (not valid in JSON)
- Undefined values (use null instead)
Common JSON errors and fixes
❌ Trailing comma: {"name": "John",}
✓ Remove the trailing comma: {"name": "John"}
❌ Single quotes: {'name': 'John'}
✓ Use double quotes: {"name": "John"}
❌ Unquoted keys: {name: 'John'}
✓ Quote the key: {"name": "John"}