Precision-engineered advanced list deduplicator & cleaner for the modern web.
About Advanced List Deduplicator & Cleaner
Advanced List Deduplicator & Cleaner is the tool you reach for when a spreadsheet has gone wrong: duplicate rows, weird whitespace, broken encoding, inconsistent formatting. It runs a careful, configurable pass over your input, highlights what it is about to change, and produces a clean output you can paste back into your workflow. Because it runs on-device, sensitive data stays with you.
Problems This Tool Solves
Spreadsheet pastes routinely arrive with duplicate rows, trailing whitespace and inconsistent capitalisation. - Advanced List Deduplicator & Cleaner normalises, deduplicates and sorts the input in one pass, with a preview before you commit.
Pasting data into an online tool means trusting a third-party server with your content. - Advanced List Deduplicator & Cleaner runs 100% inside your browser — nothing you paste is transmitted, logged, or stored.
Manual cleaning loses track of what was changed and why. - Advanced List Deduplicator & Cleaner produces a deterministic diff so you know exactly which rows were altered and how.
Cleaning tens of thousands of rows in a spreadsheet is painfully slow. - Advanced List Deduplicator & Cleaner handles hundreds of thousands of rows in the browser with no lag.
How to Use
Paste or upload your list - Supports raw paste, CSV upload and drag-and-drop of .txt and .tsv files.
Pick the cleaning rules - Toggle dedup, case, whitespace, sort, special-character stripping, and normalisation as needed.
Preview the diff - Every change is shown before it commits so you can review and adjust.
Copy or export - Download cleaned output as CSV/TXT or copy straight to clipboard.
Why This Tool Is Better
Deterministic output - The same input always produces the same output — essential for reproducible data pipelines.
Scales to big lists - Handles hundreds of thousands of rows in-browser, with no slowdown and no server upload.
Preview before commit - Every change is previewed so destructive operations can be reviewed and adjusted.