Free Online CSV Validator
Validate CSV structure for column count mismatches, malformed quotes, and BOM.
Drop your CSV file here
or click to browse from your computer
CSV, TSV, XLSX, TXT• Private in-browser processing
Private by Design — Your CSV Stays on Your Device
OnlineCSV processes your files entirely client-side using browser JavaScript. Your CSV contents are never uploaded to any server, database, or remote service.
No account requiredWorks offlineZero data transmission
How to Use CSV Validator
1
Select CSV File
Drop or paste your CSV file into the validator.
2
Review Report
Inspect highlighted errors, row locations, warnings, and suggestions.
3
Export Fixed CSV
Download a clean repaired CSV file where automatic fixes apply.
Frequently Asked Questions
What issues does it detect?
Unequal column counts, unclosed quote marks, empty headers, duplicate headers, BOM presence, and carriage return discrepancies.