There are two types of compression, lossless and lossy. RAR file compression is one of many techniques for shrinking files. As many of us live entirely on our phones with limited data plans, that’s a good thing. Alongside ZIP files, they enable us to shrink files to make them easier and faster to download. They are the primary compressed file type used on the internet. RAR files (.rar) are Roshal Archive files named after their inventor, Eugene Roshal.