System Design

These system design guides cover how to build software that scales and stays up. There are over a hundred posts, grouped by topic.

For a start, read load balancing and caching. Then high availability covers uptime. Also, each sub section goes deeper into one area.

112 articles

15/05/2016 10 min read

Build Caching Explained: Speeding Up CI Without Breaking Reproducibility

Build Caching Explained shows how to speed up CI and still ship the same bits. Learn cache keys,…
03/05/2016 10 min read

DNS for Backend Engineers: Resolution, Caching, Failover, and Debugging

DNS for Backend Engineers shows how name lookups, caches, and TTL choices fail in production, and how you…
01/04/2016 9 min read

API Gateway in System Design: The Front Door of Microservices

What an API gateway does (routing, authentication, rate limits, transformation) how it differs from a reverse proxy and…
20/03/2016 11 min read

Docker for Backend Systems: Images, Layers, Networking, and Production Hardening

Docker for Backend Systems covers images, layers, networks, and hardening. Learn what fails in production, how to cut…
29/01/2016 10 min read

How a CDN Works: Edge Caching, TTLs, and Cache Hit Ratio

How a CDN serves content from edge servers near users; cache hits, origin fetches, TTLs, cache hit ratio,…
24/01/2016 10 min read

CI/CD for Backend Engineers: Pipelines, Artifacts, and Deployment Strategies That Scale

CI/CD for Backend Engineers explains pipelines, artifacts, and safe deploys. See what breaks in production, how to scale…
26/11/2015 8 min read

Reverse Proxy Explained: The Server in Front of Your Servers

What a reverse proxy is, what it does (TLS termination, routing, security) how it differs from a forward…
24/09/2015 10 min read

Load Balancing in System Design: Types, Algorithms, and Health Checks

What a load balancer does, how L4 and L7 balancing differ, which algorithm to pick (round robin, least…
20/08/2015 10 min read

TCP vs UDP: Protocol Trade-offs for Modern Backend Systems

TCP vs UDP explains when you want reliable streams, when datagrams win, and how loss, latency, and head-of-line…
23/07/2015 12 min read

Client-Server Architecture: The Model Every System Design Builds On

Client server architecture explained: how the client server model works, stateless vs stateful servers, and the request response…
21/05/2015 9 min read

The CAP Theorem and Consistency Models, Explained Practically

CAP says that during a network partition, a distributed system must choose between consistency and availability. Precise definitions,…
19/03/2015 8 min read

Availability vs Reliability vs Durability: Precise Definitions for Engineers

Availability is uptime, reliability is correct behavior over time, durability is data survival. Exact definitions, the nines table,…
15/01/2015 9 min read

Latency vs Throughput: The Two Numbers That Define Performance

Latency is the time one request takes; throughput is how many requests you serve. How they differ, why…
08/01/2015 10 min read

Vertical vs Horizontal Scaling: Choosing How to Grow

Scaling a system isn’t always as simple as adding more resources. As your application grows, the way you…