Tools
JSON Validator
Paste JSON to instantly validate its syntax. Valid JSON shows structure stats — type, key count, and nesting depth. Invalid JSON shows the exact error with line and column numbers.
FreeError Line NumbersStructure Stats
Paste JSON to Validate
Most common JSON mistakes
- Trailing commas:
{ "a": 1, }— not allowed - Single quotes:
{'key': 'value'}— must be double quotes - Unquoted keys:
{key: "value"}— keys must be quoted - JavaScript comments:
// comment— not valid in JSON
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