JSON Copilot How do I fix JSON validation errors?
Advanced Topics
JSON syntax errors can be frustrating, but JSON Copilot makes them easy to understand and fix! Our editor provides real-time error detection with clear messages, line numbers, and helpful suggestions. Learn to interpret common validation errors and fix them quickly.
Real-Time Error Detection
The editor highlights syntax errors as you type, with red squiggly underlines and detailed error messages when you hover.
Common JSON Errors & Fixes
❌ Missing or Extra Comma
❌ Incorrect:
{
"name": "Alice"
"age": 30
}✅ Correct:
{
"name": "Alice",
"age": 30
}Fix: Add comma between properties, but NOT after the last property.
❌ Unquoted Keys
❌ Incorrect:
{
name: "Alice",
age: 30
}✅ Correct:
{
"name": "Alice",
"age": 30
}Fix: All keys must be wrapped in double quotes.
❌ Single Quotes Instead of Double
❌ Incorrect:
{
'name': 'Alice',
'age': 30
}✅ Correct:
{
"name": "Alice",
"age": 30
}Fix: JSON requires double quotes (") not single quotes (').
❌ Trailing Comma
❌ Incorrect:
{
"name": "Alice",
"age": 30,
}✅ Correct:
{
"name": "Alice",
"age": 30
}Fix: Remove comma after the last property or array element.
❌ Mismatched Brackets
❌ Incorrect:
{
"items": [1, 2, 3}
]✅ Correct:
{
"items": [1, 2, 3]
}Fix: Match opening [ with closing ], and opening { with closing }.
❌ Comments in JSON
❌ Incorrect:
{
// This is a comment
"name": "Alice"
}✅ Correct:
{
"name": "Alice"
}Fix: Standard JSON doesn't support comments. Remove them or use JSONC format.
Error Location Tips
Check Line Numbers
Error messages include line and column numbers - use Cmd/Ctrl + G to jump directly to the error location.
Bracket Matching
Click next to a bracket - the editor highlights the matching bracket to help identify mismatched pairs.
Look Above the Error
Missing commas often report errors on the next line. Check the line above for missing commas.
Use Format to Auto-Fix
If JSON is valid but poorly formatted, use Format (Option/Alt + Shift + F) to reveal structure.
Quick Fix Workflow
Look for red squiggly underlines in the editor
Hover over the underline to read the error message
Apply the fix based on the error type
Verify the error disappears as you type
Pro Tip: Copy Valid JSON First
If you're struggling with errors in manually typed JSON, try copying a small valid JSON example first, then modify it. This ensures the basic structure is correct.
Still Have Questions?
Check out our other FAQ topics or return to the JSON Copilot app