Architecture & DesignIntermediate
Stateless vs Stateful
PronunciationSTAYT-les versuhs STAYT-ful
Definition
Stateless systems do not store client session data between requests, meaning every request must contain all necessary information. Stateful systems, however, remember previous interactions and store client state on the server across multiple requests.
Where you hear it
During system design discussions, scaling planning, and when choosing how to manage user sessions and API architecture.
Examples
We need to design a stateless API so any instance behind the load-balancer can handle the request.
Shopping carts are often stateful because the server must remember what items the user added across different pages.
Migrating from a stateful architecture to a stateless one made our application much easier to scale horizontally.
Common mistake
Assuming stateless means the application never saves data anywhere, when it actually means the server doesn't keep session memory about a specific client between independent HTTP requests.
Keep exploring
More in Architecture & Design