Resulting from the technological revolution from the last decades, we observed many software startup ecosystems emerging around the globe. Having tech entrepreneurs as their main agents, some ecosystems exist for more than 50 years, while others are newly born. This difference in terms of evolution and maturity makes the task of comparing different tech hubs a challenge. Moreover, nascent ecosystems need a clear vision of how to develop their community to evolve towards a fruitful and sustainable ecosystem. This paper proposes a maturity model for software startup ecosystems based on a multiple case study of two existing ecosystems. By determining the maturity level for each ecosystem, it is possible not only to compare different realities, but mainly to identify gaps and propose customized practical actions that can lead to real improvements in the existing ecosystems, taking it to the next level of development, promoting innovation.