Emmet API Server

Emmet is a toolkit of packages designed to build the Materials API, which is the Materials Project (MP) specification for defining and disseminating “materials documents”. The `emmet-api` package specifically provides the API server component for serving these material documents. It is currently at version 0.86.3 and receives frequent development builds (e.g., 0.87.0.devX) with stable releases occurring periodically.