Scaling from the first user to millions: load, latency, capacity planning and performance engineering.
How fast are the CPU, cache, RAM and SSD? Compare latency and bandwidth in nanoseconds and GB/s, scaled to human time, and learn what it means for your code.
A stage-by-stage guide to scaling a web app — from a single server to load balancers, caching, read replicas, queues, CDNs, sharding and multi-region — and how to know when to do each.
Horizontal vs vertical scaling explained — how scaling up and scaling out work, costs, limits, statelessness, databases, autoscaling and how to choose for your application.
How to scale a database — vertical scaling, read replicas and replication lag, table partitioning, sharding strategies and shard keys, rebalancing, and alternatives to sharding.
How rate limiting works — fixed window, sliding log, sliding window counter, token bucket and leaky bucket algorithms, distributed rate limiting with Redis, headers and best practices.
How content delivery networks work — edge locations, caching, cache keys and headers, invalidation, dynamic acceleration, security benefits, edge compute and how to use a CDN well.
A practical developer guide to Core Web Vitals — what LCP, INP and CLS measure, good thresholds, how to measure with field and lab data, and concrete fixes for each metric.
A practical guide to load testing — load, stress, spike and soak tests, realistic workload modeling, key metrics, finding bottlenecks, tools like k6 and Locust, and testing safely.
The latency numbers behind system design — CPU caches, memory, SSDs, networks, data centers and continents — with practical lessons for caching, batching, databases and architecture.
What connection pooling is, why database connections are expensive, how to size pools, PgBouncer and pooling modes, serverless connection storms, HTTP connection reuse, and common pitfalls.
How to estimate traffic, storage, bandwidth and compute for a system — QPS math, peak factors, Little's Law, headroom, cost estimates and turning numbers into architecture decisions.