System Design Cheat Sheet ✧

Before choosing a tech stack, define the system's boundaries and expectations.

| Strategy | How it works | Best for | |----------|-------------|-----------| | | App checks cache → misses DB → writes cache | Read-heavy workloads | | Read-through | Cache sits in front of DB | Consistent data, complex queries | | Write-through | Write to cache + DB synchronously | Write-heavy, need consistency | | Write-behind | Write to cache → async write to DB | High write throughput, eventual consistency | | Refresh-ahead | Cache auto-refreshes near-expiry data | Predictable access patterns | system design cheat sheet

This system design cheat sheet covers the fundamental principles, components, patterns, and considerations for designing scalable and maintainable systems. It also includes evaluation criteria, common interview questions, and best practices to help you prepare for system design challenges. Before choosing a tech stack, define the system's

→ APIs, data flow Non-functional → Availability, latency, durability, consistency data flow Non-functional → Availability

Keep this sheet handy during design interviews or architecture reviews. Adapt — there is no perfect design, only trade-offs you can justify.