Remove Duplicate Lines

Instantly remove duplicate entries from any text list while preserving the original order. Perfect for cleaning email lists, data exports, and code.

Input — paste your list 0 lines · 0 chars
Output — unique lines 0 lines · 0 chars

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Why Remove Duplicate Lines?

Duplicate entries in lists are a common problem when working with data exports, email lists, log files, or any text-based dataset. Manually scanning for duplicates is tedious and error-prone, especially with hundreds or thousands of lines.

How Deduplication Works

This tool scans your list line by line, keeping only the first occurrence of each unique entry. The original order of your list is always preserved — no sorting is applied. You can enable case-insensitive mode so that "Apple" and "apple" are treated as duplicates.

Common Use Cases

Cleaning email lists before import, removing repeated entries from CRM exports, deduplicating log files, preparing unique values for SQL queries, and tidying up copy-pasted data from spreadsheets. The trim whitespace option ensures that lines differing only by leading or trailing spaces are correctly identified as duplicates.

Frequently Asked Questions

Does this tool preserve the original order of my list?
Yes. The tool keeps the first occurrence of each line and removes subsequent duplicates. Your list order remains exactly as it was, minus the repeated entries.
What does "case insensitive" do?
When enabled, "Apple" and "apple" are treated as the same entry. The first occurrence (with its original casing) is kept, and later duplicates regardless of case are removed.
Is my data safe?
Absolutely. Everything runs locally in your browser. No data is ever sent to a server, stored, or tracked.
Can I handle very large lists?
Yes. The tool processes text locally and can handle tens of thousands of lines efficiently on modern devices.