100% Client-Side:XLSX, CSV, TSV, Markdown & JSON parsing runs locally in browser memory with zero server uploads.
Vertical Append Stack & Horizontal Key Join • Zero Uploads

Merge Multiple CSV Files Online

Import your first CSV or workbook, click + Add Sheet to drop additional CSV files as tabs, then run Merge / Join Sheets to either Append Rows Vertically or match records by key column.

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Zero Uploads

Two Ways to Merge CSVs in One Click

  • Stack / Append CSV Files: Combine monthly exports or lead lists vertically while keeping headers aligned.
  • Join / Enrich by ID (Left Join): Match emails, SKUs, or order numbers across two CSV files without writing VLOOKUP or Python pandas scripts.
  • Deduplicate Immediately: Run Remove Duplicates on the combined sheet before exporting clean XLSX or CSV.