Paste a list with repeated lines and get a clean, de-duplicated version in one click.
Duplicate lines creep into lists more often than you'd expect: an email list exported twice, a to-do list that got pasted in from two different sources, a spreadsheet column copied without checking for repeats, or search results collected from multiple sites. Manually scanning for and deleting repeats in a list of any real size is slow and easy to get wrong — the human eye is not well suited to spotting an identical line buried forty rows down.
This tool removes that manual work. It reads your text one line at a time, keeps a record of every line it has already seen, and drops any line that repeats — while always preserving the first occurrence and the original order of the remaining lines. An optional "ignore case" setting treats differently-capitalized versions of the same text as duplicates too, which matters for lists like email addresses or names where capitalization is inconsistent but the underlying value is the same.
It's a favorite among anyone who manages lists for a living: marketers cleaning an email list before a send, developers de-duplicating log output or config values, students merging bibliography entries from multiple sources, and researchers combining survey responses. Because the comparison happens locally in your browser, there's no upload step — you can safely run lists containing personal or sensitive information through it without that data going anywhere else.