Rigetti Computing manufactures programmable quantum computers. As a part of that, they have developed a number of new technologies: a programming language, compiler, simulator, runtime, language bindings, and execution environment. Together, these form Forest, their quantum software development kit. We discuss Rigetti's open source quantum ecosystem, and how we see it developing in the coming year. Rigetti Computing manufactures quantum integrated circuits, and they become computers when the silicon is made programmable. Programming a quantum computer is fundamentally different than programming a classical one. The earliest quantum computers will run hybrid quantum/classical algorithms, marrying traditional software approaches with very non-traditional paradigms born out of quantum mechanics. In this light, open source quantum software serves dual purposes. First, it makes the mathematical realities of quantum computing more accessible to non-experts, and second, it leverages the vast innovations made by countless open source software engineers around the world. Both of these serve to maximize the power of near-term quantum computers. We discuss the fundamental nature of an open source quantum development ecosystem, starting with the quantum programming language Quil, and discuss how that's made into a practical tool through open source quantum software development kits. We discuss Rigetti's open source quantum ecosystem called Forest, and how we see it developing in the coming year.