Sipi is a high-performance, IIIF compatible media server developed by the Digital Humanities Lab at the University of Basel. It is designed to be used by archives, libraries, and other institutions that need to preserve high-quality images while making them available online.

Sipi implements the International Image Interoperability Framework (IIIF), and efficiently converts between image formats, preserving metadata contained in image files. In particular, if images are stored in JPEG 2000 format, Sipi can convert them on the fly to formats that are commonly used on the Internet. Sipi offers a flexible framework for specifying authentication and authorization logic in Lua scripts, and supports restricted access to images, either by reducing image dimensions or by adding watermarks. It can easily be integrated with Knora. In addition SIPI preserves most of the EXIF, IPTC and XMP metadata and can preserve or transform ICC colour profiles.

In addition, a simple webserver is integrated. The server is able to serve most common file types. In addition Lua scripts and embedded Lua (i.e., Lua embedded into HTML pages using the tags <lua>…</lua> are supported.

Sipi can also be used from the command line to convert images to/from TIFF_, JPEG 2000, JPEG_ and PNG_ formats. For all these conversion, Sipi tries to preserve all embedded metadata such as IPTC, EXIF, XMP and ICC color profiles. However, due to the limitations of some file formats, it cannot be guaranteed that all metadata and ICC profiles are preserved. JPEG 2000 does not allow all types of ICC profiles. Unsupported profile types will be added to the JPEG 2000 header as comment and will be reinstated if the JPEG 2000 file is converted back to the TIFF_ format.

Sipi is free software, released under the GNU Affero General Public License. It is written in C++ and runs on Linux (including Debian, Ubuntu, and CentOS) and Mac OS X.

Freely distributable binary releases are available.