Easy

High-level design problems suitable for 1–2 weeks of system design practice. Focus: basic architecture, simple scaling, single DB.

Problems

Problem	File	Key concepts
URL Shortener	url-shortener.md	Hashing, Base62, DB sharding, cache
Rate Limiter	rate-limiter.md	Token bucket, sliding window, Redis
Pastebin	pastebin.md	Key generation, storage, CDN
Key-Value Store	key-value-store.md	Hash map, persistence, replication

Use the HLD template and capacity estimation when practicing.