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Join CSV Files

Join two CSV files by email, ID, SKU, or another matching column with inner, left, right, and unmatched modes. Process locally in your browser with HappyCSV.

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How to use this tool

Quick start

Built for combining columns from two files using a shared id, email, sku, or key.

Everything runs in your browser, so you can test the workflow with sample data when available before using production files.

Output: A joined CSV with matched and, when selected, unmatched rows.

  1. 1Upload the two source CSVs.
  2. 2Choose the key column in each file.
  3. 3Select the join type, inspect the result, and download it.

How to Join CSV Files

  1. 1Upload the two source CSVs.
  2. 2Choose the key column in each file.
  3. 3Select the join type, inspect the result, and download it.

Why Use This Tool?

  • ✓Join two CSV files by email, ID, SKU, or another matching column with inner, left, right, and unmatched modes.
  • ✓A joined CSV with matched and, when selected, unmatched rows.
  • ✓Files are processed locally in this browser.
  • ✓Keep the source file and review the result before importing it elsewhere.

Frequently Asked Questions

What does this tool support?

A joined CSV with matched and, when selected, unmatched rows.

What are the processing limits?

Up to 100 MB per CSV, 20 MB per complex document; 250,000 rows, 1,000 columns, 2 million cells, and 128 MB output. Jobs stop after two minutes. Large files may need splitting.

Are my files uploaded?

No. File processing stays in your browser. Files are not automatically saved for the next visit.

Can I process multiple files?

Yes. Add the files required for this operation and review their order before processing.

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