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About Dedupe — Remove Duplicate Lines or Words Online
This free dedupe tool removes duplicate lines or repeated words from any block of text. Paste a log file, an email list, a column from a spreadsheet, or a CSV row, and it returns only the unique entries — telling you exactly how many duplicates it stripped out.
You control how matching works: toggle case sensitivity so "Apple" and "apple" count as one entry or two, trim surrounding whitespace before comparing, and choose whether to keep the original order or sort the results. By default the first occurrence of each item wins, so the list stays in the order you pasted it.
Everything runs entirely in your browser. Nothing you paste is uploaded, which makes it safe for cleaning up email addresses, API keys, or any other private data offline.
Features
- Remove duplicate lines or duplicate words in one click
- Optional case-insensitive matching and whitespace trimming
- Keep the original order or sort the unique results
- Reports how many duplicates were removed; works fully offline
How to use
- Paste your list into the input pane — one item per line, or words separated by spaces.
- Pick Lines or Words, and toggle case-sensitive, trim, or keep-order to taste.
- Read the status line to see how many duplicates were removed.
- Copy the deduplicated output, or clear and start again.
Frequently asked questions
Does it keep the first or last duplicate?
The first occurrence of each item is kept and later duplicates are dropped, so with "keep order" on, your list stays in its original sequence.
How do I dedupe ignoring case?
Turn off the "Case-sensitive" toggle. Then "Email", "email", and "EMAIL" are treated as the same entry, and the first spelling you pasted is the one kept.
What is the difference between Lines and Words mode?
Lines mode splits your text on newlines and removes duplicate lines. Words mode splits on any whitespace and removes duplicate words, joining the unique words back together with single spaces.
Is my text sent to a server?
No. All deduplication happens locally in your browser. Your input never leaves your device, so it is safe for sensitive lists.
Related tools
Everything runs locally in your browser — your input is never uploaded.