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Pretty-print, validate, and clean up CSV files
Compare two CSV files side-by-side, find added/removed/modified rows, key-based or positional matching, highlight differences, and download comparison report
View and edit CSV files in a spreadsheet-like interface
Duplicates creep into datasets through repeated imports, merge errors, and manual entry. This tool finds them fast. Choose which columns define a "duplicate," preview the matches, then keep the first occurrence, last occurrence, or remove all copies.
You control what counts as a duplicate by selecting one or more key columns. Two rows are considered duplicates only if they match on every selected column — so you can deduplicate by email alone, by a combination of first name + last name + zip code, or by every column at once. The tool shows each group of duplicates so you can verify before removing anything.
Remove duplicate contacts before a mail merge or CRM import.
Eliminate overlapping records after combining CSVs from multiple sources.
Identify how many duplicate records exist in a dataset and where they cluster.
Yes. Select a single column like email or ID and the tool treats rows as duplicates whenever that column value repeats.
By default yes, but you can enable case-insensitive matching so "John" and "john" are treated as the same value.
You can download a separate file containing only the removed duplicates for auditing purposes.
All processing happens directly in your browser. Your files never leave your device and are never uploaded to any server.