Stateless service.

also: stateless services · stateless server · stateless servers · stateless application · stateless

A component that keeps no client or session state between requests, so any instance can serve any request and instances are interchangeable.

the two-minute refresher

Stateful servers keep sessions in memory: users must return to the same server, and a crash logs them out.
Stateless servers push state to a shared store (Redis, a database) or the client (a signed token).
Any server can handle any request, so you add or remove servers freely: horizontal scaling becomes easy.
The state still exists; you have moved it somewhere built to be shared and durable.

also: stateless services · stateless server · stateless servers · stateless application · stateless

A component that keeps no client or session state between requests, so any instance can serve any request and instances are interchangeable.

Stateful servers keep sessions in memory: users must return to the same server, and a crash logs them out.
Stateless servers push state to a shared store (Redis, a database) or the client (a signed token).
Any server can handle any request, so you add or remove servers freely: horizontal scaling becomes easy.
The state still exists; you have moved it somewhere built to be shared and durable.