CSViser ADVISER

Validate and clean your
CSV files instantly

Upload a CSV or XLSX file, see exactly what's wrong, and fix it — no software to install, no spreadsheet skills needed.

Validate

Strict RFC 4180 validation — errors, warnings, and info messages with plain-English explanations. Know exactly what's wrong and why.

Fix common issues

One-click fixes for encoding (UTF-8, BOM, Windows-1251), mixed line endings, blank rows, extra whitespace, and inconsistent null values.

Deduplicate

Remove exact duplicate rows or use fuzzy matching to catch near-duplicates — typos, name variations, formatting differences.

Convert columns

Normalize dates, numbers, currencies, emails, phone numbers, and URLs. Auto-detects input format, converts to your chosen output.

Reshape and transform

Sort, filter rows, split columns, normalize headers, anonymize PII, split into multiple files, or merge two files by key column.

Export anywhere

Download as CSV, Excel (XLSX), JSON, or Markdown table. Upload XLSX and we convert it automatically on the way in.

How it works

1

Upload your file

CSV or XLSX, up to any size. Delimiter and encoding are detected automatically.

2

Review results

See validation errors, a column-by-column profile, and a summary of fixable issues.

3

Fix and download

Apply fixes, convert columns, reshape — then export in your preferred format.

Ready to clean your first file?

Free to use. No credit card required.