Validate

Detect and report structural errors in CSV files before importing

Audit CSV files for structural errors, encoding problems, and row-length inconsistencies.

🛡️ Your rows never leave your browser.
Why Onfyt: Reports errors with exact line numbers, column offsets, and severity levels—not just a pass/fail flag—saving import debugging time.

Interactive Sample Data

idnameemailrole
1Grace Kerubograce@example.comAdmin
2Peter, Njorogepeter@example.comUser
3Mercy Akinyimercy@

How this tool works

Importing a malformed CSV file into PostgreSQL, MySQL, or a data warehouse without pre-validation causes bulk load failures, data truncation, or silently corrupt records. Common CSV pathologies include: rows with a different number of columns than the header (ragged rows), unclosed double-quote characters that absorb subsequent rows into a single cell, embedded newline characters inside unquoted strings, and BOM characters at the start of files produced by Excel on Windows. DataFix's CSV validator parses the entire file client-side, emitting a structured report that lists every error with its exact line number and column position. The report classifies errors by severity (fatal, warning, info) so you can prioritize fixes before the import pipeline runs. Validation runs entirely inside your browser so proprietary data stays local.

Things that usually go wrong

  • CSV files with unclosed quotes cause the parser to read multiple rows as one.
  • Files with mixed delimiters (comma in most rows, semicolon in a few) are flagged.

Edge cases we tested

🧪 Quoted cell spanning three lines

Parsed as a single multi-line value; rows counted from close-quote position.

🧪 Windows BOM (\xEF\xBB\xBF) prefix

Detected and stripped; first column header reports correctly without invisible prefix character.

🧪 Trailing comma on every row

Flagged as extra empty column rather than silently accepted.

🧪 CRLF vs LF mixed in same file

Normalised before parsing; does not split lines incorrectly.

Frequently Asked Questions

What exactly is validated?

Column count consistency, proper RFC 4180 quoting, UTF-8 encoding, no null bytes, and consistent delimiter usage.

Does it fix issues automatically?

Some — it closes unclosed quotes and normalises inconsistent column counts. Complex errors are flagged for manual review.

Can I validate a file larger than 5 MB?

Yes. The tool processes the file locally in your browser using a streaming parser. Files up to 50 MB complete without sending any data to a server.

What is RFC 4180?

RFC 4180 is the de-facto standard for CSV files. It specifies that fields containing commas, double-quotes, or line breaks must be wrapped in double-quotes, and that double-quotes inside a field must be doubled.

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