CSV Toolkit

Compare, merge, deduplicate, and transform CSV files — all in your browser.

100% client-side — your files never leave your device
1Original
2Comparison
3Results
Drop original CSVClick to browse or drag and drop
.csv.tsv.txt
Drop comparison CSVClick to browse or drag and drop
.csv.tsv.txt
Built by Alex Diaz • All processing happens locally in your browser

What You Can Do

⇄

Compare (Diff)

Find differences between two CSV files. Identify added, removed, and modified rows with line numbers.

⊕

Merge

Combine two CSVs by a key column. Supports left, right, inner, and outer joins.

≡

Deduplicate

Remove duplicate rows based on selected columns. Keep first or last occurrence.

⚙

Transform

Filter rows, select columns, rename headers, and sort data.

Built for Data Professionals

  • Composite primary keys — Compare by multiple columns (e.g., sku, locale)
  • Smart change detection — Separates meaningful changes from inventory/availability noise
  • Line number tracking — Jump directly to changed rows in your files
  • No file size limits — Processing happens in your browser's memory
  • Export to JSON — Get structured diff reports matching the CLI output

Need CLI access? Check out the Data Diff Checker Python package.