Less repetition. More clarity.

Delete Duplicate Lines Online is a free utility platform for text, CSV data, developer tasks, images and practical SEO preparation.

Made for the work between the work

A copied list. An export with repeated rows. Notes full of blank lines. These small cleanup tasks should not need a spreadsheet formula, a script, or a new account. This website brings the essential controls together in one place.

Your browser does the processing

The tools run on your device. Text and uploaded files are processed locally, and the application does not store your work in browser storage. Text and data transformations use browser workers. Image tools use local browser decoding and canvas; document downloads are generated on your device. Guides are maintained through Git and delivered as static pages.

A tool for each task

• Remove duplicate lines with first, last, and single-occurrence modes.
• Inspect a repeated-line report to see what occurs more than once.
• Remove empty lines while keeping repeated content.
• Sort text alphabetically or in natural numeric order.
• Join lines with a separator of your choice.

Explore text tools, CSV tools, developer tools, file tools and SEO utilities, or read our practical guides.

Clear limits, useful defaults

The original line tools accept files up to 10 MB. Dedicated CSV tools support quoted fields, embedded commas and line breaks, with smaller limits shown in each workbench. Image and document tools also show their supported formats and limits. Device memory and browser support affect processing; keep an original copy and review every result.

Read the privacy policy for details about local processing and website hosting.