According to economists, digital platforms are two-sided markets that bring buyers and sellers together to enable exchange and create value. For Aadhaar, India’s digital identity program, while service providers requesting authentication of customer identities are on one side of the market, there is no other side, just a central database that stores and provides the relevant information. Aadhaar, in this sense, is not a two-sided marketplace, yet it is almost always referred to as a platform. This is due to the absence of a widely accepted taxonomy for India’s digital public ecosystem, resulting in disciplinary siloes among economists, technologists and legal professionals who use competing vocabulary. This policy brief is an attempt to bridge this difference and to build an interdisciplinary foundation for a taxonomy of digital public ecosystems. We define four distinct components of the digital public ecosystem and explain how these inter-relate with each other. These are digital public goods (DPGs), digital public infrastructure (DPIs), digital public platforms (DPPs) and other digitised government services (DGS). Each component is defined and illustrated using examples from India’s rapidly evolving digital public ecosystem.