How it works
Paste a list with one item per line — email addresses, keywords, file names, log entries — and every repeat after the first is dropped. The surviving lines stay in their original order, so nothing gets shuffled the way a sort-and-dedupe would.
With trimming on, "banana" and "banana " (with a trailing space) are treated as the same line, and the output is cleaned of leading and trailing spaces. Ignore case makes "Apple" and "apple" duplicates; the first spelling you wrote is the one kept. Removing empty lines also strips blank lines out of the result.
The work happens entirely in your browser, so private lists never leave your device.
Frequently asked questions
Which copy of a duplicate is kept?
Always the first one. Later copies are removed, so the order of the remaining lines matches your original list.
How can I keep only lines that appear once?
This tool keeps one copy of every line. To find lines that are repeated, compare the "removed" count, or sort the list first with the Sort Lines tool so duplicates sit next to each other.