Remove Duplicate Lines

Duplicate lines are a common data-quality problem that crops up when merging lists from different sources, processing log files, working with CSV exports, or building keyword lists for SEO and advertising campaigns. A list of 500 email addresses exported from two different systems might contain 80 duplicates. A server log might repeat the same error line thousands of times. An SEO keyword spreadsheet built from multiple tools often contains near-identical rows.

Manually scrolling and deleting duplicates is error-prone and tedious. This tool removes them instantly — paste your text, click a button, and get back only the unique lines. Options let you control whether the comparison is case-sensitive ("Apple" and "apple" as the same or different?), whether to trim whitespace before comparing (so " hello " and "hello" are treated as the same line), and whether to preserve the original order or sort the unique lines alphabetically.

The tool is useful far beyond simple word lists. Developers use it to deduplicate log output before analysis. Database administrators use it to find unique values in a text column before importing. Writers use it to tidy up citation lists. Advertisers use it to clean negative keyword lists for Google Ads and Microsoft Advertising campaigns.

The operation runs entirely in your browser — no upload, no server call. Even very large text files (tens of thousands of lines) process in milliseconds.