ZIP is used as a base file format by many programs, usually under a different name. ZIP and the MIME media type application/zip. ZIP files generally use the file extensions. Most free operating systems have built in support for ZIP in similar manners to Windows and Mac OS X. Apple has included built-in ZIP support in Mac OS X 10.3 (via BOMArchiveHelper, now Archive Utility) and later. Microsoft has included built-in ZIP support (under the name 'compressed folders') in versions of Microsoft Windows since 2000 (Windows Me).

The ZIP format was then quickly supported by many software utilities other than PKZIP. This format was originally created in 1989 and was first implemented in PKWARE, Inc.'s PKZIP utility, as a replacement for the previous ARC compression format by Thom Henderson. The ZIP file format permits a number of compression algorithms, though DEFLATE is the most common. A ZIP file may contain one or more files or directories that may have been compressed. ZIP is an archive file format that supports lossless data compression.