*EVA* (EVent & Agent) is a *visual robot programming language* used to construct *multi-robot collaboration mechanisms* using events and agents as first-class abstraction to the components and their interactions on a multi-robot system. EVA is expressive enough to support many usual models for robot algorithm modelling and implementation. EVA is designed to be supported on *ROS (Robot Operating System)* through a middleware called EVA runtime, which provides platform transparency to EVA programs. The EVA development toolkit and EVA runtime provide many useful functions for statically and dynamically generating and managing event routes automatically.