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Patterns

Recurring system design patterns. Core algorithms now live under Engineering Craft.

Learn the reason behind each component

1 independent guides. Each includes local concept explanations, a correctness contract, a worked failure trace, and a runnable Python learning model.

Read in this order: requirements → concepts → data flow → concurrency and failure behavior → sizing → worked example. Explain what can fail before choosing a technology.

01·Common PatternsChoose reusable design mechanisms from requirements and explain their correctness costs before choosing products.

Find a guide or concept

1 guides

Common Patterns — System Design

Choose reusable design mechanisms from requirements and explain their correctness costs before choosing products.

Cache-aside and invalidation · Optimistic concurrency and compare-and-set · Fencing tokens · Transactional outbox · Sagas and compensation · Geohash · Backpressure and load shedding · Idempotency keys

Download the Python concept models · Python 3.10+, no packages required.

Student clarity and correctness review · 19 October 2026