Remove Duplicate Lines

Two lines are duplicates when they match exactly, character for character. The first time a line appears it is kept; any later identical line is removed. The original order of the surviving lines is preserved.

No. Duplicates are removed across the whole text, not just consecutive ones. A line near the bottom that matches a line near the top is still removed.

Matching is exact: two lines count as duplicates only when every character matches, including case. "Apple" and "apple" are different lines, so both survive. For case-insensitive deduplication, convert the text to lowercase first, then remove duplicates. For example, a list containing "SALES@acme.com" and "sales@acme.com" keeps both entries until you lowercase it, after which only the first remains.

Yes. " apple" and "apple" differ because of the spaces. Run Trim Text first if you want lines that differ only in surrounding whitespace to be treated as duplicates.

Paste the list with one email address per line, and the tool keeps the first occurrence of each address while deleting every exact repeat. For example, a subscriber export of 500 lines where "jo@example.com" appears three times comes back with that address once, in its original position. Because matching is case-sensitive, lowercase the list first so "Jo@Example.com" and "jo@example.com" collapse into one entry. The same steps work for deduplicating a URL list.

Paste the log and the output contains each distinct line once, at the position where it first appeared. For example, a server log with 2,000 repeats of "connection timeout" collapses to a single line, so every distinct error becomes visible at a glance. One caveat: lines that carry unique timestamps never match each other, so strip the timestamp column first if you want identical messages to merge.

Removing duplicate lines deletes repeated content; removing blank lines deletes empty rows and keeps repeats. Use this tool when the same entry appears more than once, and Remove Blank Lines when the problem is empty gaps. For example, a list with "apple", an empty line, then "apple" again keeps "apple" and the empty line here. Repeated blank lines do count as duplicates of each other, so only the first empty line survives.

The order never changes: every surviving line stays exactly where it first appeared, and only later repeats are deleted. What looks like reordering is a removed repeat. For example, if "beta" sits at line 2 and again at line 9, the copy at line 9 disappears and the lines below it shift up. Compare the output against the first occurrence of each entry and the sequence matches your input.

With this tool, yes: deduplication runs entirely in your browser and the list is never uploaded to a server. Your addresses stay on your device, and closing the tab discards them. For example, you can dedupe a 10,000-line subscriber export offline: load the page once, disconnect from the internet, and duplicate removal still works because no network request is involved.