System Design

Overview

Design the architecture before writing code. Define service boundaries, data flow, API contracts, and infrastructure. Make trade-off decisions explicit.

Core principle: Architecture mistakes are 100x more expensive to fix than code mistakes. Think first, build second.

When to Use

• Starting a new project or microservice
• Adding a major feature that changes system boundaries
• Scaling beyond current architecture
• After product-spec, before scaffolding

Design Process

1. Requirements Extraction