In this talk at the CECAM 2015 Workshop on Future Technologies in Automated Atomistic Simulations, I will discuss the Materials Project Ecosystem, an initiative to develop a comprehensive set of open-source software and data tools for materials informatics. The Materials Project is a US Department of Energy-funded initiative to make the computed properties of all known inorganic materials publicly available to all materials researchers to accelerate materials innovation. Today, the Materials Project database boasts more than 58,000 materials, covering a broad range of properties, including energetic properties (e.g., phase and aqueous stability, reaction energies), electronic structure (bandstructures, DOSs) and structural and mechanical properties (e.g., elastic constants). A linchpin of the Materials Project is its robust data and software infrastructure, built on best open-source software development practices such as continuous testing and integration, and comprehensive documentation. I will provide an overview of the open-source software modules that have been developed for materials analysis (Python Materials Genomics), error handling (Custodian) and scientific workflow management (FireWorks), as well as the Materials API, a first-of-its-kind interface for accessing materials data based on REpresentational State Transfer (REST) principles. I will show a materials researcher may use and build on these software and data tools for materials informatics as well as to accelerate his own research.