In large software systems, knowing the dependencies between modules or components is critical to assess the impact of changes. To recover the dependencies, fact extractors analyze the system as a whole and build the dependency graph, parsing the system down to the statement level. At the level of software ecosystems, which are collections of software projects, the dependencies that need to be recovered reside not only within the individual systems, but also between the libraries, frameworks, and entire software systems that make up the complete ecosystem; scaling issues arise. In this paper we present and evaluate several variants of a lightweight and scalable approach to recover dependencies between the software projects of an ecosystem. We evaluate our recovery algorithms on the Squeak 3.10 Universe, an ecosystem containing more than 200 software projects. © 2010 ACM.