Does the order of the original list matter?

Yes. The deduper preserves the original order of the lines it keeps. With "keep first" the first occurrence wins; with "keep last" the last occurrence wins. Either way, surviving lines stay in their original relative positions.

How does it treat lines that differ only in whitespace?

When "Trim each line before comparing" is on, " apple " and "apple" count as the same line. Turn it off to treat them as different. Trimming also normalizes the kept line so the output has no stray whitespace.

Will it dedupe across different cases like "Apple" and "apple"?

Only when "Case sensitive" is unchecked (the default). Turn it on to keep mixed-case duplicates separate — useful for case-significant identifiers like API keys.

Is the original list sent anywhere?

No. The deduper runs entirely in your browser using a hash set. Nothing is uploaded, logged, or transmitted.

Duplicate Line Remover

Paste a list and remove duplicate lines while keeping the first or last occurrence. Toggle case sensitivity and whitespace handling.

Lines to dedupe

Options

Case sensitiveTrim each line before comparingRemove blank linesKeep first occurrence (uncheck to keep last)

How to remove duplicate lines from a list

Strip duplicate lines from any list with case-sensitivity, whitespace, and first-vs-last controls.

Open the Duplicate Line Remover
Go to makemytxt.com/duplicate-line-remover. There is nothing to install or sign up for.
Paste your list
Paste any list — emails, IDs, error logs, CSV rows. Each line is treated as a single record for comparison.
Choose comparison options
Decide whether the comparison is case-sensitive, whether each line is trimmed before comparing, and whether blank lines should be dropped.
Pick keep-first or keep-last and copy the result
Keep the first or the last occurrence of each duplicate. The summary shows how many duplicates were removed; use Copy or Download to save the deduped list.

Frequently asked questions

Does the order of the original list matter?: Yes. The deduper preserves the original order of the lines it keeps. With "keep first" the first occurrence wins; with "keep last" the last occurrence wins. Either way, surviving lines stay in their original relative positions.
How does it treat lines that differ only in whitespace?: When "Trim each line before comparing" is on, " apple " and "apple" count as the same line. Turn it off to treat them as different. Trimming also normalizes the kept line so the output has no stray whitespace.
Will it dedupe across different cases like "Apple" and "apple"?: Only when "Case sensitive" is unchecked (the default). Turn it on to keep mixed-case duplicates separate — useful for case-significant identifiers like API keys.
Is the original list sent anywhere?: No. The deduper runs entirely in your browser using a hash set. Nothing is uploaded, logged, or transmitted.

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