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 must a Kafka consumer set isolation.level=read_committed to get exactly once downstream?

Without it the consumer sees records from aborted transactions, which are duplicates that should have been rolled back, The default isolation level is read_uncommitted. It silently exposes records from aborted transactions, which breaks exactly once downstream. This is the most common end to end exactly once bug and it never shows up in tests because tests rarely abort transactions.

What happens if Flink crashes between preCommit (phase 1) and commit (phase 2) of a TwoPhaseCommitSinkFunction?

The prepared Kafka transaction is aborted on recovery and records never become visible to consumers, Recovery restores the latest checkpoint and aborts any prepared but uncommitted transactions from the crashed incarnation. The records were never visible to read_committed consumers, so no duplicates. The new job instance replays from the checkpointed offset and rewrites the records in a new transaction.

A pipeline writes to a REST API that has no idempotency key support. What is the honest guarantee?

At least once, because a retry after a timeout can duplicate a request that actually succeeded, Without idempotency keys, a timeout followed by a retry can create a duplicate if the original request succeeded but the response was lost. This is at least once semantics. The honest answer is to document it, add a dedup layer downstream, or add idempotency key support to the API.

Exactly-Once Semantics

Name: System Design Masterclass
Availability: InStock

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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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