Remove Duplicate Lines Online — Dedupe Array & List
Tool interface
When to use a duplicate-line remover
Why dedupe lists online?
Logs, CRM exports, keyword dumps, and pasted arrays often contain the same line many times.
Cleaning that by hand is slow and error-prone. This tool unique-ifies one-item-per-line text
in the browser — the same idea as Array.from(new Set(lines)) for strings —
without uploading your data.
Practical use cases
Email / ID lists
Merge campaign or survey lists and keep one row per address or user ID before you send or import.
SEO keyword cleanup
Combine Search Console and tool exports, then drop duplicate queries into a clean unique list.
Error-pattern scanning
Paste noisy log lines and keep unique messages so you can see which error types actually occur.
Tag / category extraction
Copy a column of tags from a spreadsheet and produce a unique vocabulary for filters or taxonomies.
Case sensitivity
Decide whether Apple and apple count as the same value.
- Case-sensitive (default): Best for IDs, paths, and code where casing matters.
- Case-insensitive: Better for hand-typed emails (
[email protected]vs[email protected]).
Local-only processing
Customer lists and internal logs stay in your browser. Nothing is uploaded. Safe to use offline after the page loads.