JSON errors are among the most common (and annoying) issues developers face. A missing comma, an extra quote, or a trailing comma can break an entire API response. Here's a practical workflow to debug them fast.
1. Validate first, don't eyeball
Don't scan a 200-line JSON by eye. Paste it into a validator that tells you the exact line and column of the error. This alone saves minutes every time.
2. Check the common culprits
-
Trailing commas -
[1, 2, 3,]is invalid in strict JSON - Unescaped quotes inside string values
- Single quotes instead of double quotes
- Comments - JSON doesn't allow them (unlike JSONC)
- Missing colons between key and value
3. Format before you read
A minified blob is unreadable. Beautify it first - with proper indentation, structural mistakes become visually obvious.
4. Diff large changes
When a JSON response changes between deploys, use a diff tool to spot exactly what shifted instead of comparing manually.
5. Use the right tool
For quick work I use JSONMini - it's free, runs 100% in your browser, and gives you precise error line/column positions, a tree view with image previews, side-by-side diff, custom indentation, and URL sharing via the ?json= parameter. Your data never leaves your machine.
Happy debugging!
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