# Architecture Stack

> **System design case studies + patterns** — shared by both the [indian-sde-faang lane](../lanes/indian-sde-faang/INDEX.md) and the [abroad-full-stack lane](../lanes/abroad-full-stack/INDEX.md).

| Section | Files | Topics |
|---------|------:|--------|
| [System-Design](system-design/INDEX.md) | 22 | URL shortener, WhatsApp, Uber, Netflix, payment gateway, ticket booking, 17 case studies |

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**Lane-specific overlays:** Add interview strategy context, behavioral stories, and prep plans in [Interview Lanes](../lanes/INDEX.md) — the stacks stay stack-pure.