This is the interactive version of the Compendium of Sanitation Systems and Technologies by TILLEY ET AL (2014), a compilation of appropriate sanitation technologies, plus a tool for combining technologies in a full system. The compendium’s popularity is due to its brevity - ordering and structuring a huge range of information on tried and tested technologies in a single document. As in the first edition only proven technologies that are appropriate for low- and middle-income settings are presented. Also, only "improved" sanitation technologies, featuring safe, hygienic, and accessible sanitation are included. The whole range of urban, peri-urban and rural technologies (e.g. from simple pits to conventional sewers) is presented in the eCompendium.