scAPAdb provides a comprehensive and manually curated atlas of poly(A) sites, APA events and poly(A) signals at the single-cell level in six species based on a large volume of scRNA-seq data. Currently, scAPAdb records APA information in animal species including Homo sapiens (human), Mus musculus (mouse) as well as plant species including Oryza sativa L. (rice japonica and indica), Arabidopsis thaliana, Zea mays (corn) and Chlamydomonas reinhardtii (Chlamy).