Polyadenylation [poly(A)] is an essential process during the maturation of most 
mRNAs in eukaryotes. Alternative polyadenylation (APA) as an important layer of 
gene expression regulation has been increasingly recognized in various species. 
Here, a web platform for visualization and analysis of alternative 
polyadenylation (VAAPA) was developed. This platform can visualize the 
distribution of poly(A) sites and poly(A) clusters of a gene or a section of a 
chromosome. It can also highlight genes with switched APA sites among different 
conditions. VAAPA is an easy-to-use web-based tool that provides functions of 
poly(A) site query, data uploading, downloading, and APA sites visualization. It 
was designed in a multi-tier architecture and developed based on Smart GWT 
(Google Web Toolkit) using Java as the development language. VAAPA will be a 
valuable addition to the community for the comprehensive study of APA, not only 
by making the high quality poly(A) site data more accessible, but also by 
providing users with numerous valuable functions for poly(A) site analysis and 
visualization.