Digital services involving large systems with multiple users are ubiquitous in modern society. The systems are often complicated and made up of multiple devices and communication protocols. A fundamental problem in this context is how the behavior of a system changes as the number of users vary. In particular, when do the systems’ resources saturate and how does the system behave when close to saturation. Performance testing is key for addressing this fundamental problem. Performance testing is the scope of this project. Performance tests can be used for inference of, for example, a system's scalability. Furthermore, it can be used to provide general guarantees on the services that can be delivered. Performance testing at the company Phoniro AB is considered. The platform Phoniro Care is the back-end service for the company’s products. The Phoiro 6000 system is one of the products that uses Phoniro Care. The system allows for multiple users and offers alarm services. The primary focus of this project is to determine the behavior of that system during varying levels of simulated load, and furthermore analyze the data extracted from such simulations and tests. The open source software JMeter was used as the tool for performance testing. It was selected from a set of candidate tools that have been evaluated in the literature based on various performance criteria. The results are presented by graphs showing the time evolution of different performance indicators. A conclusion from this work is that the implemented performance testing framework helps to answer questions about the systems’ behavior. Questions that are important for the company’s further development and expansion of the system. Furthermore, the proposed framework establishes a foundation for further inquiries on the subject.