Stateful vs Stateless

State is essentially the condition of the entity at a particular instant of time.

In a stateful web service, the web server stores the data at some backend technology(server or database) and uses it to identify the connected client.

For example, when a user tries to log into an application with username and password. If the server stores this data, and then uses it to allow connectivity, the service is stateful.

Statelessness is the polar opposite of statefulness. The server is independent of any sort of state. Drawing from the above example, the credentials can be cached on the client’s device but not stored on the server. All the requests in a stateless service take place as an isolated functionality. This means that, the request is unaware of other requests and will rather carry all the information than rely on a previous call or stored information on the server side.