Everyday millions of letters are redirected from old to new addresses of their recipients. It happens because people are changing their homes or job, so the companies changing their location. In order to avoid sending the letters to old and then to the new addresses, which spends lots of recourses, a new generation of Postal Automated Redirection System /PARS/ is applied in USPS. The PARS consists of more than 50 processing sorting centers /P&DC/ equipped with special optical character recognition SW which automatically redirects the letters to the new addresses. This paper presents the design and development of WEB-based Performance Diagnostic System /PDS/ intended to operative control, monitoring and diagnostics of PARS HW and SW components, as well diagnostics and analysis of sorted letters. The PDS can be used for on-line remote control of PARS and the quality and performance of the sorting process.