How can one perform load/stress test against an IoT specific application? New Innovative/Intelligent IoT enablers (Intelligent Gateway) are being designed and developed to support custom applications in abundance. It is important to stress test each of these devices. Building thousands of low end sensor devices for the sole purpose of generating data is not a viable solution. Scenario can be even more challenging if the application is suppose to handle hits from multitude of heterogeneous devices that uses different protocols to communicate. If so, DeVi can bridge the gap. It is an Open Source Solution from the IoT & BigData Research labs, Amrita Cybersecurity Center, Amrita Vishwa Vidyapeetham. It will let the users to spin off several sensor clusters comprising of thousands of heter,br.ogeneous devices by using a simple, easy to configure GUI. Devices can then push data onto the IoT application to test its robustness. There is also a Visualization component that will visualize the virtual devices, their status, data transmission density etc. In the next release of DeVi, it will be possible to map a virtual gateway with an actual gateway device so that Intelligent devices can also be stress tested.