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.

Why is the HttpOnly flag critical on a session cookie?

It prevents JavaScript from reading the cookie, blocking XSS-based session theft, HttpOnly tells the browser to block JavaScript access to the cookie via document.cookie. This means even if an attacker injects XSS, they cannot steal the session ID and send it to their server.

A user logs out but keeps a copy of their session cookie. Can they re-use it?

No, because the server deleted the session from Redis, so the ID points to nothing, When the server processes a logout, it deletes the session key from Redis (DEL session:abc). The cookie still exists in the attacker's copy, but when the server tries to look up that session ID, Redis returns nothing. The session ID is now an orphan pointing to deleted data.

You have 4 servers behind a load balancer. All 4 store sessions in local memory. A user logs in on Server A, then their next request goes to Server B. What happens?

Server B cannot find the session and returns 401 Unauthorized, In-memory sessions are local to the process. Server B has no knowledge of the session created on Server A. The solution is a shared session store (Redis) or sticky sessions at the load balancer. Redis is almost always the better choice because sticky sessions create uneven load and lose sessions on server restarts.

Cookie-Based Sessions

Name: System Design Masterclass
Availability: InStock

in Security Architecture

This lesson is part of the full System Design Masterclass. Unlock it along with 765 other lessons for a one-time payment.

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$19.99$7.99/lifetime

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Foundation lessons free, try before you buy

Founders price, locked for the first 10,000 customers

India Special

India

₹999₹499/lifetime

One-time via UPI, cards, or net banking

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Foundation lessons free, try before you buy

Founders price, locked for the first 10,000 customers

“The interactive diagrams alone are worth way more than the price.”

Anish K., Senior Engineer at a Bengaluru startup

All 766 interactive lessons

Step-by-step animated diagrams

Live code editors with real execution

Quizzes with instant feedback

Completion certificates per level

Lifetime access, all future content included

The first 5 Foundation lessons are free, no payment needed. Try them now