CSV header fixer
Fix duplicate CSV headers
Review duplicate or blank column names and export a CSV with repaired headers.
Processed in your browser. Your file is not uploaded.Drop a CSV file here
UTF-8, UTF-8 BOM, and Windows-1252 are supported. Limit: 25 MB.
What this tool changes
Enables the repair for duplicate and empty headers, adding safe unique names where needed.
What to review
Review the preview before importing because renamed headers may need to match your destination's expected field names.
How it works
Add your file, review the detected settings and output, then download the result. Processing stays in your browser.
Questions
What happens to duplicate headers?
Fixmerce creates unique header names so the CSV has a usable header row.
Will this map fields for my marketplace?
No. It repairs the CSV header structure; you still choose the correct import fields in your destination.
Related tools
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Start with the problem closest to yours. Each option opens the same local tool with relevant settings selected.