GetData is a library that provides an API to interface with dirfile databases. The dirfile database format is designed to provide a fast, scalable format for storing and reading binary, synchronously-sampled, time-ordered data. GetData was originally written for the BOOMERanG and BLAST experiments as a data format suitable for use for both quick-look and data reduction. It is now used by many other cosmological and astrophysical experiments including ACT, Planck, Spider, Keck, as well as other projects.