OpenHBCI -- the first free client-side implementation of the HBCI specification. HBCI is a bank-independent homebanking standard used by many German banks. This publicly available protocol describes communication, authentification, encryption, and business transactions taking place between a homebanking applications and a bank's server. OpenHBCI provides an object oriented library implementing the current client-side HBCI specification. The library is written in C++, with C wrappers also available. OpenHBCI provides the application programmer with a high-level abstraction of almost all business transactions, so that all HBCI details are totally encapsulated and do not need to be bothered with.