Remove duplicate lines

Clean email lists, keywords, identifiers, URLs, log excerpts, inventory values, or any multiline text without uploading it. FileGizmo preserves the first occurrence of each line and removes only later matches, so the original order remains stable and predictable.

Enable surrounding-space handling when lines should match despite accidental indentation or trailing spaces. The kept line retains its original formatting; trimming is used only to create the comparison key. Optional case-insensitive matching treats values such as Example and example as duplicates while preserving the first spelling. The result reports exactly how many lines were removed and how many remain.

All comparison work happens immediately in the browser using a set-based algorithm that scales linearly with the input size. No text is sent to a server or stored in an account. Review the cleaned output separately, copy it to the clipboard, or download a UTF-8 text file. Keyboard-friendly controls and responsive layouts keep the workflow comfortable on desktop and mobile.

The first occurrence of each line is kept and later ones are dropped, so the original order survives. That is the behaviour people expect from a list they have curated: the ranking stays intact and only the repeats disappear. Sorting first would lose that, which is why sorting is a separate tool.

You are told how many lines were removed. A deduplicated list that comes back the same length usually means the duplicates differ in some invisible way, most often trailing whitespace from a spreadsheet export, and a count of zero is the fastest way to discover that.

The common uses are mailing lists assembled from several sources, log lines where the same error repeats, and keyword lists merged from separate exports. All of them share a property that makes manual checking hopeless: the duplicates are rarely adjacent.

Blank lines between entries are treated as lines like any other, so a list padded with spacing keeps one blank and loses the rest. If you need the spacing preserved exactly, deduplicate before adding it.

The list stays in your browser. Contact lists and internal logs are precisely the material that should not be pasted into an unknown server to be tidied up.