FLOW is an on-line database that aims to provide an easy-access synthesis of available biological published primary data on planthoppers (Hemiptera, Fulgoromorpha), a group of major economic importance. It includes information on names, taxa (including fossils), and their classification but also on type depositories, bibliography, distribution and associated biological information such as host-plants. FLOW provides a dynamic link to MNHN Hemiptera specimen collection (particularly type specimens), GBIF occurrences, and provides photos when already available. Dynamic syntheses are also provided for all suprageneric taxa.