When I first started learning web development, I often came across the terms “stateful” and “stateless” — especially when people talked about backend APIs, frontend apps, or server design. It sounded fancy at first, but once I understood what state actually means, everything made sense.
So let’s start from the basics.
What Do “Stateful” and “Stateless” Mean?
In simple terms, state means remembering something.
If a system remembers what happened earlier — it’s stateful.
If it forgets everything after each interaction — it’s stateless.
Think of it like talking to two different shopkeepers:
A stateful shopkeeper remembers what you bought last week.
A stateless one treats you like a brand-new customer every single time.
Frontend: Stateful vs Stateless
In the frontend, state refers to the UI data stored in the browser or app memory — like user inputs, selections, all variables or data fetched from APIs.
Stateful Frontend
A stateful frontend keeps track of what’s going on — it remembers the user’s actions or data even when things change.
Example:
A React app that stores login info in context or Redux store.
A chat app that maintains active messages or typing state without reloading.
A game that remembers current score and progress.
These apps store data in state variables or local storage — so they know what’s happening between renders.
Stateless Frontend
A stateless frontend doesn’t remember anything. Each time we load the page, it starts fresh.
Example:
A static HTML site built with plain HTML/CSS/JS that just fetches data and displays it without saving any context.
A simple portfolio website or landing page — no dynamic memory or user context.
Backend: Stateful vs Stateless
The same idea applies to the backend too, but here it’s about server memory and client sessions.
Stateful Backend
A stateful backend stores user data or sessions on the server between requests.
Example:
Traditional applications using sessions or cookies to remember the user (like older PHP apps).
WebSocket servers that keep a live connection with each client — like chat or multiplayer games.
Any server that needs to maintain long-term user context (like logged-in sessions or ongoing transactions).
The downside? It’s harder to scale — because every user’s data lives on a specific server instance. And we know that how much
Stateless Backend
A stateless backend doesn’t store anything about previous requests. Each API call is independent.
Example:
REST APIs or serverless functions (like AWS Lambda, Firebase Functions).
Each request carries all the info needed (like tokens in headers).
Perfect for horizontal scaling, as any server can handle any request.
This is why most modern backends are stateless — they’re simpler to scale, cache, and deploy.
What’s Preferred (and Why)
On the Frontend
Frontend apps are usually stateful, because they handle user interactions, UI updates, and temporary storage of data.
Without state, your app would feel static and disconnected.
However, developers manage it carefully — too much state makes debugging painful.
That’s why tools like React, Redux, Recoil, or Zustand exist to manage state efficiently.(Recoil my personal fav)
On the Backend
Backends are generally preferred to be stateless.
Why? Because:
They’re easier to scale horizontally.
Requests can be distributed across multiple servers.
No dependency on specific instances or memory.
When backend systems need to “remember” something, they usually offload it to a database, cache, or token-based session — rather than keeping it in memory.
That’s the sweet spot where most modern apps live today.
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