Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker. Smart 3D Web API uses Redis to cache URL requests for faster retrieval. However, if Redis is not installed, the caching is done in memory. You can install Redis on a Linux server or use a hosted Redis service. Redis is available from https://redis.io/download. For the best performance, we recommend installing Redis on a computer with at least two cores on the same network subnet as the IIS server.