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Strip repeating lines with optional case-insensitive matching, trimming, keep-last and sort.
This is a free, browser-based duplicate line remover that strips repeating lines from any text, with options for case-insensitive matching, whitespace trimming, keeping the first or last occurrence and optional sorting — all running in JavaScript on your own machine, so nothing is uploaded.
Paste your list and the deduplicated result appears instantly. Toggle case-insensitive matching, trim whitespace before comparing, choose to keep the first or last occurrence and optionally sort. It all runs in your browser — nothing is uploaded.
Paste your lines on the left, one per row. Toggle the options you want — case-insensitive, trim, keep last, sort — and the deduplicated result updates instantly on the right with the line counts. Copy or download the result. Nothing is sent to a server.
No. Everything runs in your browser, so even sensitive email lists and customer IDs stay private.
Repeated blank lines collapse to a single blank line by default since they compare equal; turn on Trim if you want even whitespace-only lines treated as blank.
When duplicates exist, keep-first preserves the line where it first appears in your input; keep-last preserves the most recent copy, useful when later entries overwrite earlier ones.
Built by the Toolbox team using a single-pass Set for stable O(n) deduplication and locale-aware case folding, so big lists stay fast and Unicode duplicates are matched correctly.