Pen-based technologies can be combined with different kinds of hardware and software to gain pedagogical benefits on blended learning applications. Particularly, digital ink and handwriting recognition furnish the convenience to access, navigate and manipulate data more easily. It is also well know that user interfaces for pen computing can be implemented in several ways, with different techniques and for several kinds of applications. A modular programming architecture for pen-based digital ink was developed in order to provide a robust, reliable, usable and sustainable multimedia technology for a blended learning application. We present this approach and the respective advantages.