123apps is a collection of online tools for common file tasks: video editing, audio conversion, PDF merging and splitting, screen recording, and more. The idea is that you shouldn't need to install a 500MB program just to convert a file or trim a video. Everything runs in the browser. You upload a file, choose your settings, process it, and download the result. The tools are straightforward and the interface is clean.

There are limits on file size and processing time for free users, and the site is supported by ads, but for occasional tasks it's more than sufficient. It's useful when you're on a computer that doesn't have the software you need, or when you just don't want to deal with installing something for a one-time job. The PDF tools and audio converters are particularly handy.