Does it preserve order?

Yes. The first occurrence of each line is kept.

What does case sensitivity do?

When on, 'Apple' and 'apple' are treated as different.

No hard limit — bounded only by your browser memory.

Strip duplicate lines from a list, optionally case sensitive.

Case sensitive

Duplicates removed

Cleans a list by keeping only the first occurrence of each line.

Sort lines alphabetically A→Z or Z→A.

Collapse multiple spaces, trim lines and optionally drop blank lines.

Pull all unique email addresses out of a chunk of text.