Google Cloud Datastore was a NoSQL database service provided by Google Cloud Platform. It is now superseded by Firestore which offers a "Datastore compatibility" mode to ensure legacy applications built on Datastore continue operating seamlessly. Google Cloud Datastore API organizes data in entities and properties, where entities are grouped into kinds. This concept is similar to tables in relational databases, however since this is NoSQL database, it is without the schema constraints. Each entity in Datastore is uniquely identified by a key. This key can have a custom user-defined identifier or it can be auto generated key by the system.