Remove Duplicate Lines
Strip repeated lines from a list and keep only the first occurrence of each.
Remove Duplicate Lines
Clean up any list by deleting repeated lines. Choose case-sensitive matching to treat "Apple" and "apple" as different, or case-insensitive to collapse them into one. The first occurrence of each line is always kept.
What it does
- Keeps the first occurrence of each line
- Case-sensitive or case-insensitive matching
- Preserves the original line order
- Handles thousands of lines instantly
Great for cleaning data
Use it to tidy up email lists, log files, keyword lists, CSV columns, or any dataset where duplicate rows have crept in.
Case sensitivity matters
Whether duplicates should be matched exactly or regardless of case depends on your data. For names and codes you often want exact matching; for free-text lists, case-insensitive matching usually removes more noise.
100% Private & Processed Locally
Every conversion on this page runs entirely inside your browser using JavaScript. Your data is never uploaded to a server, logged, or stored â making this tool safe even for sensitive payloads such as API responses, configuration files, and access tokens.
Because there is no network round-trip, conversions are instant and work even when you are offline. It is free to use with no sign-up, no rate limits, and no ads injected into your output.
Frequently Asked Questions
Common questions about the Remove Duplicate Lines.