Table of Contents

Solution Architecture: Building Blocks & Patterns

How software systems are built, piece by piece.

What Is a Software System?

Every application — a food delivery app, an online bank, a streaming platform — is made up of building blocks connected together following a pattern.

• Building blocks = the components (frontend, database, cache, etc.)
• Patterns = how you arrange and connect them (monolith, microservices, etc.)
• Architecture = the decisions about which blocks to use, which pattern to follow, and what trade-offs you accept

There is no "correct" architecture. Only trade-offs.

Part 1: The Building Blocks

No system uses all of them. Knowing when to reach for each one is more important than knowing what they are.

Frontend → What the user sees

• Web apps (React, Vue, Angular), mobile apps (iOS, Android), desktop apps
• Talks to the backend via APIs
• A single system can have multiple frontends — e.g. a customer app, an admin dashboard, and a staff tablet view — all sharing the same backend