System Design Foundations

Monolith vs microservices in 2026 — the differences that matter, why team size (not traffic) decides it, and when to start with a modular monolith.

7 min

Kafka vs RabbitMQ in 2026 — why it's a log versus a queue (not fast versus slow), the differences that matter, and when each one (or both) is the right call.

7 min

Caching strategies in 2026 — the patterns (cache-aside, write-through, write-behind), eviction policies, and why cache invalidation, not adding a cache, is the genuinely hard part.

7 min

System design building blocks explained as a decision map — the five questions that pick your components (architecture style, cache, message broker, database, load balancer) and how each block earns its place.

6 min

Load balancers explained in 2026 — L4 vs L7, the algorithms, and why health checks (not even distribution) are the part that actually keeps you online.

5 min

SQL vs NoSQL in 2026 — why the real choice is about access patterns and correctness, not scale; the four NoSQL types; and why most systems end up using both.

5 min

API gateway explained in 2026 — what it actually does (auth, rate limiting, routing, aggregation), why it's not a load balancer, and where the new AI gateway fits.

4 min

Event-driven architecture explained in 2026 — events vs commands, choreography vs orchestration, and the real trade-off: you gain decoupling and lose the single view of what happens next.

5 min

CAP theorem explained in 2026 — why 'pick two of three' is wrong, the real consistency-vs-availability choice during a partition, PACELC, and what it means for AI systems.

5 min

Horizontal vs vertical scaling in 2026 — scale up (a bigger box) versus scale out (more boxes), the hardware ceiling, why horizontal needs statelessness, and the diagonal middle ground.

5 min

Rate limiting explained in 2026 — fixed window, sliding window, token bucket, and leaky bucket, which algorithm to default to, and why LLM traffic is limited by tokens rather than requests.

5 min

CDNs and object storage explained in 2026 — object storage as the origin for large files, CDNs as the edge cache near users, how they work together, and what they store in AI systems.

5 min