Djatoka is an open source JPEG 2000 image server that allows for fast extraction of regions of interest and quality layers from JPEG 2000 files. It uses a tile caching system to improve performance. URIs can be used to access specific regions, rotations, levels and formats of an image. While open source, it relies on the proprietary Kakadu library for JPEG 2000 encoding and decoding. Installation and setup are straightforward but it requires Tomcat 5.5 or higher to run.