System Design

A structured end-to-end guide for designing systems from scratch, making architecture decisions, estimating capacity, and building for scalability and reliability.

When to Activate

• Designing a new service, platform, or system from scratch
• Writing a design document, tech spec, or RFC
• Making a technology selection or architecture decision
• Writing an Architecture Decision Record (ADR)
• Reviewing a design for scalability, reliability, or security gaps
• Planning capacity for a feature expected to handle significant load

Design Process

Follow these six steps in order. Each step informs the next — skipping steps leads to rework.