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.

Stripe allows 100 requests per second per API key with a burst capacity of 25. What algorithm makes this possible?

Token bucket that accumulates tokens at a steady rate and allows spending them in bursts, Token bucket stores saved-up tokens. A client that has been idle accumulates tokens up to the burst capacity (25). When it fires 25 requests at once, the bucket drains instantly, then refills at 100 tokens per second. The long-term average is bounded at 100/s while short bursts are allowed.

An engineer building a distributed rate limiter uses Redis INCR and EXPIRE as two separate commands without a Lua script. What bug will appear in production?

The INCR and EXPIRE can race, leaving orphaned counters that never expire and eventually filling Redis memory, If the process crashes between INCR and EXPIRE, the key exists but has no TTL. Over time, millions of orphaned counters accumulate and Redis runs out of memory. A Lua script wrapping both commands runs atomically inside Redis, eliminating the race.

Redis goes down and the rate limiter must decide what to do. Why do most public APIs choose fail-open while internal admin APIs choose fail-closed?

For public APIs, a self-inflicted outage from a broken limiter is worse than brief overshoot. For admin APIs, unlimited admin actions during an outage is more dangerous., The fail mode depends on what is worse: the limiter being down (fail open, allow everything) or the traffic being unchecked (fail closed, reject everything). For user-facing APIs, availability matters most. For admin APIs, safety matters most.

Why is setting token bucket burst capacity equal to the average rate a design mistake?

It defeats the purpose of token bucket because if burst equals average, a simple fixed-rate counter would work just as well with less complexity, The entire reason to choose token bucket over a simpler algorithm is to allow short-term bursts above the average. If burst equals average, you get the complexity of token bucket with the behavior of a fixed counter. Set burst to 3-10x the average rate for the pattern to deliver value.

Rate Limiting for Resilience

Name: System Design Masterclass
Availability: InStock

in Reliability Resilience

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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