Remove Duplicate Lines
Remove duplicate lines from any list — keeps the first occurrence of each unique line and preserves order. Free, instant, client-side deduplicator.
🔒 100% Client-Side Processing
Your data is processed entirely in your browser and never transmitted to any server.
0 / 100M Limit
Common Use Cases
Cleaning mailing lists
Remove repeated addresses after merging signup exports so nobody receives the same campaign twice.
Merging data exports
Combine two CSV extracts or log pulls and drop the overlapping rows before analysis.
Deduplicating keyword lists
Collapse repeated terms after combining keyword research from several tools into one master list.
Frequently Asked Questions
- Does deduplication preserve the order of my list?
- Yes — the tool keeps the first occurrence of each unique line in its original position and drops later repeats, using a JavaScript Set. Nothing is sorted or rearranged.
- Is the duplicate comparison case-sensitive?
- Yes — "Apple" and "apple" count as different lines, and so do lines with trailing spaces. Normalise case with the Lowercase Converter and strip stray whitespace first for aggressive deduplication.
- Is my data private when I use this tool?
- Yes. This tool runs entirely in your browser using client-side JavaScript — nothing you type is transmitted to, logged by, or stored on any server. You can safely process confidential text, tokens, or code.