This chapter covers the URL shortening service scale requirements: users, QPS, storage, latency SLA, and availability.

This chapter covers identifying key design questions before starting: read vs write ratio, custom aliases, analytics, expiry.

This chapter covers a simple single-server design with a relational DB and its failure modes at scale.

This chapter covers a distributed design with consistent hashing, caching, and multi-region CDN.

This chapter covers two alternative approaches: Base62 encoding vs hash-based IDs, with trade-offs.

This chapter covers how Bitly, TinyURL, and Instagram handle URL shortening in production.

This chapter covers transferable lessons on ID generation, cache-first reads, and async analytics.

This chapter covers common failures: hash collisions, redirect loops, cache stampede, and analytics data loss.