Tidy pasted text in one go: spaces, empty lines, duplicates, sorting and find & replace.
Tidy up messy copy-pasted text in one click: trim spaces, remove empty lines, strip duplicate lines, sort a list, join lines into a paragraph, or replace a word everywhere.
No. It stays in your browser.
Yes. Tick "Remove duplicate lines" — it keeps the first copy and ignores upper/lower case if you choose.