CSV Deduplicator
Drop duplicate records — compare entire rows or just key columns, with optional case-insensitive and whitespace-trimming matching. First occurrence always wins.
How it works
Rows are compared on the parsed values, not the raw text — so "Ada" and Ada
are the same record even though their quoting differs. With Key column(s) you name the
columns that identify a record (header names, or 1-based positions without a header); duplicates in
those columns are removed while all other columns may differ. Ignore case and
Trim spaces relax the comparison, which is exactly what you want for e-mail lists
collected from forms.
FAQ
Which duplicate is kept?
The first occurrence in file order. Everything after it that matches is removed.
Are my rows uploaded?
No — deduplication runs entirely in your browser, safe for customer and mailing lists.