The paper presents the long-term project “Online Dictionary of Surnames in Germany” (“Digitales Familiennamenwörterbuch, DFD”), its conception, main objectives, and its technical realisation. By means of representative examples, the paper depicts how the project works along the categories of conflation, validation, specification or revision of etymologies so far proposed in standard references and the development of new ones. Exploiting new digital resources — especially with the help of new findings in surname geography, the surname stock can be captured and analysed all-encompassing and systematically. Surnames of foreign origin like English, French, Italian, Slavic, Baltic or Turkish are also considered. The importance of Slavic roots in German surnames is exemplified by the name Novak (‛new settler’) which ranks position 156 in the total frequency of German surnames. The article’s outlook discusses the importance and possibilities for future cooperation with surname projects in other countries like Poland, with a long-term perspective for a European network of surname dictionaries.