What does duplicate line removal do?
This tool scans your text line by line and removes any line that has already appeared earlier in the list. The comparison is case-insensitive, so "Apple" and "apple" are treated as the same item. The original order of the first occurrence is preserved.
When is this useful?
Cleaning email lists, deduplicating exported CSV rows, removing repeated keywords from an SEO list, consolidating log lines, or tidying up any list that was assembled from multiple sources and may contain repetitions. It is much faster than manually scanning for duplicates.
Case-insensitive comparison
Duplicates are detected without regard to capitalisation. This prevents near-duplicates like "London" and "london" from both appearing in the output. The first occurrence is kept exactly as written — only the case-matching duplicates that appear later are removed.
Tip: combine with Text Sorter
For a fully cleaned and alphabetically ordered list, first remove duplicates here, then paste the result into the Text Sorter to sort A to Z. This two-step workflow gives you a canonical, sorted, unique list ready for any purpose.