Hld
A shop ledger page, 1899. Every line adds up.
HLD Fundamentals for Beginners: Estimation, Building Blocks and a Payments Lens
A beginner-friendly system design primer: the 6-step framework, back-of-envelope QPS math, L4 vs L7 load balancing, caching, databases, queues, reliability patterns and how a payment flows end to end.
7 min read