Stateless web application vs stateful web application

 

The difference between a stateless and a stateful web application lies in how they handle and retain information (state) about user sessions or interactions.

 twtech Quick Comparison

Feature	Stateless Application	Stateful Application
State Retention	Doesn’t retain user state between requests	Remembers user state across multiple requests
Session Handling	Each request is independent	Requests are part of a continuous session
Scalability	Easier to scale horizontally	Harder to scale; session info must be replicated/shared
Resilience	More fault-tolerant	Can lose session info if a server fails
Typical Use Case	RESTful APIs, microservices, public websites	Shopping carts, user dashboards, live chats
Session Storage	Client-side (e.g., tokens, cookies)	Server-side (e.g., in-memory session or database)

 Stateless Web Application

Definition:
A stateless application does not store any information about the client's previous requests.

Example:
A RESTful API where each request includes everything the server needs (e.g., token authentication) and is processed in isolation. Context is not retained.

Benefits:

• Easier to scale (no sticky sessions).
• Simple infrastructure.
• Great for containerized apps and load balancing.

 Stateful Web Application

Definition:
A stateful application retains context (state) about the client between requests — such as login sessions, shopping carts, user preferences.

Example:
An online shopping site that remembers what’s in your cart as you browse.

Challenges:

• Requires session storage (server memory, Redis, DB).
• Load balancers need to support session stickiness or shared session state.
• More complex to scale horizontally.

 twtech Summary Analogy

• Stateless: Like asking a question at an information booth every time without introducing oneself — they don’t know who the are.  Context is not retained.
• Stateful: Like checking in at a hotel — they remember the room, preferences, and previous interactions. Context is retained.