Good performance is important for an application to run smoothly for the end user, but good tools and documentation are just as important for a developer in order tobe able to create good applications in the shortest amount of time.  This paper is comparing the cross-platform frameworks Flutter and Xamarin to find the respective strengths of the frameworks and which one is the better option and in what aspect, the newer Flutter or the well established Xamarin. We did this by studying related works to the topic as well as building applications in each framework with methods to test the performance of the applications, all the while trying out the tools and documentation of each framework. Our initial hypothes is was that Xamarin as a mature framework would perform better on average and it would also have more well developed tools. However we instead found Xamarin severely lacking compared to the newer Flutter framework and were at best equal or just slightly better. Flutter outperformed Xamarin in CPU performance, at times 3 times better than Xamarin, Flutter’s application size being almost half of the Xamarin application and the Flutter application load times were also faster. The tools were for most parts equal but the results of the documentations were split, with Xamarin having better component documentation with code examples for the components and Flutter having inconsistencies in documentation structure. However the Xamarin documentation was severely lacking in updated documentation and confusing instructions at places. The only things Xamarin performed better on were the number of lines in the codeas well as being marginally better performing at the RAM capacity test. The conclusion would be that Flutter is a well performing framework that continues to develop while Xamarin feels stagnant and most of its development seems to have slowed down over the last two years