A critical determinant of the success of digital platforms is the availability of third-party complements. In order to foster the creation of such complements, platforms often rely on boundary resources: software tools and libraries that support and lower the costs of developing complementary innovations. However, while such boundary components are increasingly widespread, little is understood about how these components shape subsequent innovation outcomes and the overall platform generativity. Here, we focus on a particularly important form of boundary resource for digital platforms: Middleware components for software development. We theorize how middleware may shape both the novelty of products being created and their subsequent market value, and propose a number of mechanisms for these effects, for which we provide evidence. We test for these different mechanisms by looking at the development of console games during 6th and 7th generation of gaming consoles. We find that the introduction of licensed middleware such as third-party game and graphics engines lead to the creation of less novel, but more commercially successful products. We attribute this to the fact that middleware allows firms to reallocate resources from developing basic functionality (such as programming how the graphics will be rendered for the target platform), to other elements that make games more valuable and successful on the market (such as story or game mechanic innovation). Our results have implications for how we think about the impact of boundary resources such as middleware on digital platforms, and recombinant innovation more broadly.