Google Cloud Datastore is a NoSQL database service provided by Google Cloud Platform. It is a fully managed database which can handle massive amounts of data and it is a part of the many services offered by Google Cloud Platform. It is designed to handle structured data (mostly document based like JSON format) and it also offers a high reliability and efficient platform to create scalable applications. Unlike traditional relational databases, this is a schema-less database concept.  This gives flexible data modeling and dynamic schema changes without downtime in its services that rely on this database. Google Cloud Datastore is platform used for data handling on mobile apps, web applications, and also the IoT systems. This is because of its key characteristics such as automatic scaling, strong consistency, and smooth integration with other Google Cloud services. Google Cloud Datastore is built to handle software applications that are require high scalability, low-latency reads and writes, and automatic management of data across distributed systems. Google Cloud Datastore 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.

Google Cloud Datastore offers an API and client libraries for different types of general purpose programming languages, like Python, Java, and Node.js. This API also has different release versions of these languages, so that Cloud Datastore can be integrated with both legacy and modern apps written in these languages. It also provides support for asynchronous operations. With this, developers can build non-blocking and highly responsive systems. In the context of data consistency, Google Cloud Datastore provides strong consistency for single entity lookups and supports eventual consistency for queries across multiple entities.

Google Cloud Datastore was announced on April 11, 2013, as a fully managed NoSQL document database and designed to support large-scale web and mobile applications. It was based on the original Datastore used in Google App Engine since 2008. But it was designed to offer feature such as scalability, higher availability, and automatic data replication across multiple data centers.

Before the launch of Cloud Datastore, developers on Google App Engine used to work on a built-in Datastore that only worked with App Engine apps. When Google Cloud Platform started to grow in the market, developers wanted a database which they could use outside of App Engine to integrate with their apps. They needed more flexibility and wide availability. Cloud Datastore met this need by adding features like automatic sharding, indexing, and support for eventual consistency.

Google launched Cloud Firestore in 2018. It was a new NoSQL database with features such as real-time updates, offline support, and faster query execution. It was supposed to replace Cloud Datastore. New users were encouraged to use Firestore instead. However, since many developers were still creating applications that were using Datastore, Google decided to rename it to "Datastore mode in Firestore" in 2020. By doing so, existing users could continue using the familiar Datastore features with an option to upgrade to Firestore later when needed.

Even after the rise of Firestore, Cloud Datastore is still widely used in legacy applications, especially those apps that need a managed NoSQL database with strong multi-region replication and automatic scaling. Google Cloud continues to support these legacy systems so that they remain reliable and fully functional even in the future.

Users can use the database in Google Cloud Datastore using the Google Cloud Console, the gcloud command-line tool. They can also use client libraries for different programming languages. Based on the user need, they can choose to either use graphical interface or writing a code to interact with the database.

Data is organized into entities in Google Cloud Datastore. These are like individual records. These entities are grouped into kinds. This is just like tables in a traditional database. However, unlike relational databases, entities in the same kind do not have to follow a fixed structure (like a pre-defined schema). They can have different sets of properties.