This Phase of the SDLC deals with the development, unit testing and integration testing of the system (application) modules, screens and reports. In addition, this Phase will address the preparation and establishment of the technical environment for development, testing and training of user representatives.

This Phase is usually carried out in parallel with the development of user procedures and user documentation from the Implementation Phase. Both of these will be required for module testing, upon the completion of the Development Phase. Co-ordination of the activities of the Development and Implementation Phases is a key responsibility of the Project Manager.

Any special procedures for data conversion are also developed and tested. The process of developing and testing of data conversion modules is no different from those required for the system itself.