Finalist was originally developed as a mainframe (Assembler - BAL) product designed and built to perform USPS® CASS™ processing on customer's addresses as the first step in the process to obtain USPS® postal discounts using PAVE™. Additional Finalist products were developed for the Windows and UNIX platforms. Finalist was also adapted for the CICS and IMS mainframe environments.
To optimize performance and take advantage of technical advancements, the Finalist source code base was unified on all platforms and Finalist was re-written into C. The new Finalist interface merged the Assembler code that called programs (APIs) like FINAL, and the Windows and UNIX applications that called programs (APIs) like ProcessAddress.
To minimize required changes for mainframe customers, the Assembler interface was kept through the Compatibility Interface (CI). Support for the CI was originally planned to last two years, to provide time for the mainframe platform to rewrite to the new (native) interface with routines like PBFNInit, PBFNProcess, and PBFNTerminate. Windows and UNIX users were required to re-write their code immediately.