Duplicate Lines Remover

Duplicate line removal is a common data cleaning task when working with lists exported from databases, spreadsheets, web scrapers, or log files. Email marketing lists frequently contain duplicate addresses from multiple import sources. Keyword research exports from SEO tools contain overlapping terms from different seed keywords. Server log analysis produces repeated IP addresses or URLs. DNS zone file exports may contain duplicate records. This tool processes the text in your browser, preserves the original order (unless sorting is requested), and outputs only the first occurrence of each unique line — optionally with case-insensitive matching to catch duplicates that differ only in capitalization.