Demand-side flexibility has gained attention as a powerful tool to increase the flexibility of the electricity system and counteract the uncertainties caused by the increase of Renewable Energy Sources. Up to date, few markets allow the participation of Demand Aggregators, which are key to make use of the flexibility of small consumers. Therefore, research surrounding demand aggregation is in many cases limited to simulations or resource consuming pilot programs. This project integrates a microgrid laboratory with a commercial aggregation platform in order to set up and configure the necessary tools to operate the laboratory as a platform to test flexibility. The flexibility platform defined in this work offers a customizable and controllable environment for Demand Response and aggregation testing, while providing a realistic assessment due to the consideration of a commercial aggregator and the use of real and emulated devices. As a first application of the platform, two customer types have been defined and tested: a residential one with a Heating Ventilation and Air Conditioning Unit and a prosumer owning a second-life Electric Vehicle battery in a solar Photovoltaic self- consumption system. The scenarios have shown how, for defined users, the interaction with the aggregator can be beneficial for all sides, as long as proper activations and incentives are defined for the customers. Through future applications of the platform, new use cases can be covered and used to gather valuable information for the aggregator or any interested stakeholder.