Duplicate Line Remover
Paste any list or block of text and instantly remove duplicate lines, keeping the first occurrence of each.
🔒 Processed locally in your browser
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How to use
- Paste or type your text into the input box, with one item or line per row.
- Optionally enable "Case-insensitive" to treat lines like "Foo" and "foo" as duplicates.
- Optionally enable "Trim whitespace" to ignore leading/trailing spaces when comparing lines, or "Sort output alphabetically" to reorder the result instead of keeping the original order.
- The result updates live below — the first occurrence of each line is always kept. Use Copy to copy it, or Reset to start over.
Features
- Removes duplicate lines while always keeping the first occurrence
- Optional case-insensitive matching for near-duplicate lines
- Optional whitespace trimming so stray spaces don't count as differences
- Optional alphabetical sorting of the deduplicated output
- 100% client-side — your text never leaves your browser
Frequently asked questions
Does my text get uploaded anywhere?
No. Duplicate Line Remover runs entirely in your browser — your text is processed locally and is never sent to a server.
Which occurrence of a duplicate line is kept?
The first one. If the same line appears multiple times, every occurrence after the first is removed and the original order of the remaining lines is preserved, unless you enable sorting.
What does "Case-insensitive" do?
When enabled, lines that differ only in letter case — like "Apple" and "apple" — are treated as duplicates and only the first is kept. The kept line retains its original casing.
What does "Trim whitespace" do?
When enabled, leading and trailing spaces are ignored when comparing lines, so " apple" and "apple " are treated as duplicates. The output still shows the original, untrimmed text of the line that was kept.
Is there a limit to how much text I can process?
No hard limit is enforced, but very large inputs (hundreds of thousands of lines) may feel slower since everything runs in your browser rather than on a server.