Is this a video course?

No. This is an interactive, slide-based learning platform. Each lesson has rich text, animated diagrams, live code editors, and quizzes. You learn by reading, interacting, and doing, not by watching videos passively.

How long do I have access?

Forever. Both pricing tiers are one-time payments with lifetime access. This includes all current 766 lessons and any future content we add.

What level of experience do I need?

None. We start from absolute basics like 'What is latency?' and build up to distributed consensus protocols. The Foundation level assumes zero prior knowledge of system design.

How much does the system design course cost?

7.99 US dollars for lifetime access globally, or 499 Indian rupees for lifetime access in India. One-time payment, no subscription, no hidden fees. 11 lessons are free with no signup required.

What technologies are covered?

Everything from DNS and load balancers to Kubernetes, Kafka, distributed databases, consensus protocols, stream processing, security architecture, and observability. We cover principles and real-world implementations used at Netflix, Google, Amazon, Uber, Stripe, and more.

Is this useful for system design interview preparation?

Yes. The lessons are structured around the exact topics asked in system design interviews at FAANG and top-tier companies. Interactive diagrams help you practice whiteboard-style explanations. Covers everything from URL shortener design to distributed payment systems.

How is this different from ByteByteGo or Educative?

766 interactive lessons (4x more than most competitors), 16 different diagram types that build step by step, real production examples from Netflix, Google, Amazon, Uber, and Stripe, and lifetime access for a one-time payment of $7.99 instead of annual subscriptions costing 100 to 200 dollars per year.

You have 3 application servers behind a load balancer. A user logs in on Server A, then their next request goes to Server B and they appear logged out. What's the root cause?

Session state is stored in Server A's memory instead of a shared store like Redis, If session data lives in Server A's memory, Server B has no knowledge of it. When the load balancer routes the next request to Server B, it can't find the session. The fix is to store sessions in a shared store (Redis) that all servers can access, making the application servers themselves stateless.

Which of these is inherently stateful and can't easily be made stateless?

A WebSocket-based multiplayer game server tracking player positions in real time, A multiplayer game server must maintain the game state (player positions, health, physics) in memory continuously. Each player action depends on the current game state. You can't send the entire game state with every player input, it would be too slow and too large. REST APIs, CDNs, and serverless functions are all naturally stateless.

What does 'push state down and out' mean in practice?

Keep application servers stateless and store state in dedicated systems like Redis and databases, The principle means keeping your application/compute servers stateless for scaling and resilience, while storing necessary state in purpose-built systems (Redis for ephemeral state, databases for persistent state). This way you get the operational benefits of stateless compute (easy scaling, simple deploys, fault tolerance) with the statefulness your application actually needs.

A startup is building a REST API. They're not sure if they should use stateless or stateful servers. Traffic is unpredictable, some days 100 users, some days 10,000. What should they do?

Stateless, it scales horizontally, which handles unpredictable traffic, and any server can handle any request, For a REST API with unpredictable traffic, stateless is the clear winner. Need more capacity? Add servers. Traffic drops? Remove servers. A server crashes? Others pick up the slack. With stateful servers and sticky sessions, scaling is harder and a single server failure means some users lose their sessions.

Stateless vs Stateful Systems

Name: System Design Masterclass
Availability: InStock

in Core Fundamentals

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