Duplicate Line, Sentence & Paragraph Remover

No. Every comparison and removal runs in your browser's own JavaScript engine — nothing you type, paste, or drop as a file is ever sent to a server. You can confirm this yourself by watching your browser's DevTools Network tab while using the tool.

"Keep first occurrence only" is the standard dedupe: it removes every repeat but leaves one copy of each item, so nothing you typed disappears entirely. "Remove all duplicates" is more aggressive — it strips out every occurrence of any item that appears more than once, including the first, leaving only the items that were already unique. Use the first to clean a list; use the second to find what's genuinely one-of-a-kind.

Sentences are split on a run of periods, exclamation marks, or question marks followed by whitespace — the same detection Word Counter uses for its sentence count — and a trailing fragment with no terminal punctuation still counts as one sentence. Paragraphs are split on one or more blank lines by default; if the text has no blank-line breaks at all (common in chat exports or plain-text copies of web content, which often separate paragraphs with a single line break instead), each non-blank line is treated as its own paragraph instead, so that style of text still gets compared rather than read as one undividable block. Neither is a full grammar parser, so an abbreviation like "Dr." mid-sentence can occasionally be read as a sentence break — review the highlighted results before trusting an automatic removal on prose-heavy text.

Line removal preserves your exact line structure, since that precision matters for lists, CSV rows, and log lines. Sentence and paragraph removal rejoin the remaining text with a single space or a blank line rather than reproducing each removed item's exact original surrounding whitespace — a deliberate simplification, since prose cleanup doesn't depend on byte-exact spacing the way line-based data does.

Hover a highlighted item in the text box, or its chip below, and a small popup names its line number, whether it's the original or a later copy, and every other line the same content appears at. This is deliberately hover-only rather than shown at all times, so the box and chip list stay readable instead of every item carrying a permanent line-number label.

Yes — click into the text box wherever that line, sentence, or paragraph is, then click "Remove current line" (the label follows whichever granularity you have selected). Whatever your cursor is currently on is highlighted live in the box as you move around, so you can see exactly what would be removed before clicking — and hovering a chip previews that specific occurrence the same way. It removes whatever's under the cursor regardless of duplicate status, separate from the duplicate-specific chips and bulk actions.

Yes — "Undo" and "Redo" next to "Remove current line" step backward and forward through every change, several steps deep, not just the last one; Ctrl+Z and Ctrl+Y (Cmd+Z / Cmd+Shift+Z on a Mac) work too, from anywhere on the page, not just while the text box itself is focused. This is a dedicated history the tool keeps itself, not your browser's native undo — every removal here replaces the box's content programmatically, which a browser's built-in undo doesn't reliably track the way it tracks ordinary typing.

It opens Diff Checker in a new tab with your original text on one side and your current, edited text on the other, so you can see exactly what a removal changed. The text is handed off entirely within your browser (no upload, no server) and isn't limited by a shareable link's usual size cap — it comfortably handles tens of thousands of characters. "View diff" only turns on once a removal action has actually changed the text; typing a fresh edit into the box resets what it compares against, since at that point there's nothing left to diff against the "before" you started with.