Stateless
A system where each request contains all the information needed to process it. The server doesn't remember previous requests. Easier to scale horizontally.
What is Stateless?
A system where each request contains all the information needed to process it. The server doesn't remember previous requests. Easier to scale horizontally.
Stateless is a foundational concept that sits in the Core Fundamentals area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Stateless" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn Stateless in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the Stateless lessonRelated lessons
Lessons that touch on Stateless as part of a larger topic.
Token-Based Authentication
Stateless authentication using signed tokens instead of server-side sessions
intermediate · security architecture
Stateless Stream Processing
Transform events independently, filtering, mapping, and routing without maintaining state
advanced · stream batch processing
Stateless vs Stateful Systems
Two fundamental architecture patterns that shape how systems handle data, scale, and recover from failure
foundation · core fundamentals
Session Management
How servers remember who you are between requests in a stateless protocol
foundation · core fundamentals
Sticky Sessions
Pinning users to the same server, when stateless just isn't possible
foundation · load balancing proxies
See also
Related glossary terms you might want to look up next.
Stateful
A system that remembers previous interactions. The server keeps track of client state between requests, making it harder to scale but sometimes necessary.
Session
A way to maintain state across multiple HTTP requests. The server stores data about a user and gives them a session ID (usually in a cookie).
Horizontal Scaling
Adding more machines to handle increased load (scaling out). Like opening more checkout lanes instead of making one cashier faster.