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List Deduplicator & Sorter

A List Deduplicator removes duplicate lines from a pasted list, optionally trims whitespace, normalises case for comparison, and sorts the result alphabetically, by length, or in reverse — all in the browser using native JavaScript Set and Intl.Collator.

Input · 0 lines
Output · 0 unique
(empty)

About List Deduplicator & Sorter

Paste a list (one item per line) — email addresses, log entries, research notes, anything. Toggle case-insensitive matching, whitespace trimming, and empty-line removal. Pick a sort order and the cleaned list updates instantly with a summary of how many duplicates were removed. The dedupe runs in O(N) via a Set; sorting uses the locale-aware Intl.Collator for natural ordering.

What List Deduplicator & Sorter does

  • O(N) deduplication via native Set
  • Locale-aware sorting via Intl.Collator (natural order)
  • Case-insensitive matching toggle
  • Whitespace-trim and empty-line filters
  • Sort options: A–Z, Z–A, shortest, longest, shuffle (CSPRNG)
  • Summary line showing how many duplicates were removed

When to reach for List Deduplicator & Sorter

  • Cleaning a list of email addresses pulled from multiple sources
  • Deduplicating tags pasted from a CMS export
  • Alphabetizing an ingredient list before grouping a shopping run
  • Shuffling a list to randomize a draw or assignment

How to use List Deduplicator & Sorter

  1. 01

    Paste your list

    Paste a list with one item per line.

  2. 02

    Configure cleaning

    Toggle case-insensitive matching, whitespace trimming, and empty-line removal.

  3. 03

    Pick a sort

    A–Z, Z–A, length-based, or shuffle. Or leave it off to keep original order.

  4. 04

    Copy the cleaned list

    Click Copy to grab the deduplicated, sorted result.

When to use List Deduplicator & Sorter vs alternatives

AlternativeUse List Deduplicator & Sorter when…Use the alternative when…
`sort -u` or `awk '!seen[$0]++'` in the terminalyou want a paste-and-go UI with case-insensitive toggles.you are scripting and want this in a pipeline.
Excel 'Remove Duplicates'the list is one column of plain text.the data is already in a multi-column spreadsheet.

Frequently asked questions

Is the original order preserved when I don't sort?
Yes. With sorting off, deduplication keeps the first occurrence of each line in original order — the same behavior as awk '!seen[$0]++' from a shell.
How does case-insensitive matching work?
When enabled, 'Apple' and 'apple' are treated as duplicates. The output uses the casing of the first occurrence.
Can I sort by length or randomise?
Yes — sort options include alphabetical (locale-aware), reverse alphabetical, shortest-first, longest-first, and shuffle (uses crypto.getRandomValues for an unbiased random order).

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