System design learning path: from fundamentals to WhatsApp, YouTube and Stripe

An eight-week path that teaches software engineers to design large systems: core building blocks, three architecture styles, then full designs of WhatsApp, YouTube and Stripe, with a quiz after every module.

Goal: every engineer can take a vague product idea, ask the right questions, estimate the load, sketch an architecture and defend its trade-offs, using one repeatable method.

Audience: backend, full-stack and mobile engineers, tech leads and architects. Basic knowledge of web APIs and databases is assumed.

Format: 8 modules, about 3 hours per week. Each module has a short talk, self-study reading, one design exercise and a 5-question quiz (pass mark 4 of 5). The three case studies each include an architecture diagram and worked numbers.

The design method used in every module

1. Clarify requirements, both functional and non-functional (scale, latency, availability, consistency).
2. Estimate load and storage with back-of-envelope math.
3. Define the API and the core data model.
4. Draw the high-level architecture.
5. Deep dive on the hardest two or three parts.
6. Name the trade-offs, failure modes and what you would monitor.

Levels

Outcomes by the end

• Size a system from users and usage, and spot the bottleneck before building.
• Choose between monolith, microservices and event-driven styles, and say why.
• Reason about replication, partitioning, transactions and consistency.
• Design a chat system, a video platform and a payment system, including failure handling.

The series

Each post ends with a quiz. Answers are hidden in a collapsible block, so try the questions first.