System design for beginners (1/10): Metrics, QPS, and CAP theorem
What is system design? Free 10-part course: requirements, QPS, p99, availability, CAP—ShortLink traffic estimates from 1 to 1M users. Roadmap: learn-system-design-basics-from-scratch
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System Design course for beginners — scale systems from 1 to 1M users · Part 1/10▼
Table of contents▼
System Design basics — scale from 1 → 1,000,000 users — Part 1/10
Running case study: ShortLink (URL shortener, redirect, click counts).
You need basic HTTP, APIs, and relational CRUD — not prior distributed-systems experience.
What a design session answers
- Clarify scope and v1 features
- Estimate traffic and storage
- Define APIs and core schema
- Draw a high-level diagram
- Find the first bottleneck
- Deep-dive only where it matters
Metrics
Design for peak QPS, track p99 latency, and set availability targets (e.g. 99.9%).
ShortLink is read-heavy: redirects dominate writes.
Back-of-envelope (1M MAU sketch)
~300k DAU × 5 redirects/day ≈ 1.5M redirects/day → ~17 RPS average; multiply by 10 for a conservative peak planning number.
CAP (practical)
Strong consistency for slug creation; eventual consistency is fine for aggregated click counts.
Course roadmap
Monolith → managed DB → cache/CDN → replicas → load balancing → queues → sharding/multi-region.
Next: Part 2 — single-user monolith
Series navigation: Part 2 →
Frequently asked questions
How is system design different from algorithm interviews?
Algorithms focus on single-machine complexity. System design focuses on multi-machine trade-offs: network, storage, latency, cost, and reliability.
Do I need Kubernetes first?
No. This course explains components conceptually; orchestration comes after you know why horizontal scaling is needed.
Continue reading
URL shortener capstone (10/10): System design at 1M MAU
URL shortener interview spec: 20k redirect RPS, 200 writes/s, p99 and availability—rubric and sample solution.
Read more →Monolith system design (2/10): Single-server MVP architecture
MVP system design: monolith, Nginx, single PostgreSQL—URL shortener API, SQL schema, redirect flow, failure modes before scaling.
Read more →Database scaling (3/10): ~100 users — managed Postgres & pooling
~100 users system design: managed PostgreSQL, connection pooling, health checks, and backups.
Read more →Does your startup need a tech partner?
Free chat about MVP, timeline, and the right profit-sharing approach.