Philologic is a free, open source full-text search, retrieval and analysis tool developed by the ARTFL Project and the Digital Library Development Centre, at the University of Chicago. This tool supports a wide variety of XML and SGML encoded documents, in addition to plain text, Dublin Core and HTML, and includes a MySQL back end. It is designed ot be light, fast and robust, boasts extensive use and testing, and can be used directly 'out of the box' with numerous configuration options built in.

Juxta is a free, open source tool for comparing and collating texts, originally intended for comparing multiple versions of the same text. It offers several views and visualization options, including histograms and side by side comparison. Juxta is available as both a desktop application and as a web service that can be integrated into the user's own website.

Superfastmatch is designed to find exact duplicates of text strings between documents.