Software package managers facilitate reuse and rapid construc- tion of software systems. Since evermore software is distributed via package managers, researchers and practitioners require ex- plicit data of software dependency networks that are opaquely formed by dependency relations between software packages. To reason about increasingly complex software products and ecosys- tems, researchers and practitioners rely either on publicly available datasets like the seemingly unattended libraries.io [15] or they mine problem-specific data from software ecosystems repeatedly and non-transparently. Therefore, we present the DaSEA dataset, which contains metadata of software packages, their versions, and de- pendencies from multiple ecosystems (currently six programming languages and five operating system package managers). Alongside the dataset, we provide an extensible open-source tool under the same name that is used to create updated versions of the DaSEA dataset allowing studies of evolution of software ecosystems.