In the present work, an investigation is developed that leads to the analysis, design, development and implementation of the inventory and billing controller software for SMEs Cymif, in which the Xp development methodology is used, this methodology contains a series of stages that are must comply to achieve the final result (software), the use of free tools contributes to the development of the project (Java, Xubuntu 14.0.0 lts), the implemented software demonstrated the great solution to technical shortcomings in SMEs, improving control of your inventory in Stock.