Nowadays applications need to deal with a large number of concurrent requests. These systems must be stress tested to ensure that they can function correctly under a load. In this context, a research field called Search-based Software Testing has become increasingly important. Most of the search-based test methods are based on single objective optimization. In the case of multi-objective optimization of tests, usually researchers assign different weight values to different objectives and combine them as a single objective. This research paper verifies the use of a multi-objective algorithm in search-based stress testing. The NSGA-II algorithm was implemented in the IAdapter tool using the jMetal framework. IAdapter is a JMeter plugin used for performing search-based stress tests. jMetal is an object-oriented Java-based framework for multi-objective optimization with metaheuristics. One experiment was conducted to validate the proposed approach.