Blog
System Design Notes
We publish two posts each week focused on practical architecture decisions you can apply in interviews and production systems.
New posts every Tuesday and Friday. Each post links to topic hubs, guided labs, and challenges so you can practice immediately.
Current Posts
Apr 10, 2026 · 9 min read
Notification System Design at Scale
How to design a multi-channel notification system that handles email, push, SMS, and in-app notifications without overwhelming users or losing messages.
Apr 7, 2026 · 10 min read
Real-Time Chat System Design: From WebSockets to Message Delivery
How to design a chat system that handles millions of concurrent connections, guarantees message ordering, and supports offline delivery.
Apr 1, 2026 · 8 min read
CAP Theorem: A Practical Guide for System Designers
What the CAP theorem actually says, what it does not say, and how to use it as a design heuristic rather than an absolute law.
Mar 31, 2026 · 9 min read
Database Replication Patterns for System Design
Leader-follower, multi-leader, and leaderless replication compared. How to handle replication lag, failover, and split-brain without losing data.
Mar 24, 2026 · 10 min read
Microservices Architecture: When to Split and When to Stay Monolithic
A practical framework for deciding whether to decompose a monolith, which boundaries to draw, and how to avoid distributed monolith anti-patterns.
Mar 17, 2026 · 8 min read
Rate Limiting Algorithms for System Design
Token bucket, sliding window, and fixed window compared. Where to enforce limits and how to communicate them to clients without breaking integrations.
Mar 10, 2026 · 10 min read
API Design Patterns Every System Designer Should Know
REST, GraphQL, gRPC, and webhook patterns compared. How to version, paginate, and rate-limit your API without painting yourself into a corner.
Mar 6, 2026 · 8 min read
Consistent Hashing Explained: How It Works in Distributed Systems
Understand consistent hashing from first principles: why naive modular hashing breaks, how the hash ring works, and when to use virtual nodes.
Mar 5, 2026 · 9 min read
CDN in System Design: When and How to Use a Content Delivery Network
Learn when a CDN actually helps, how edge caching works, and the cache-key and purge decisions that matter in real architectures.
Mar 4, 2026 · 10 min read
Back-of-the-Envelope Estimation for System Design Interviews
A step-by-step framework for capacity estimation: QPS, storage, bandwidth, and memory calculations that interviewers actually expect.
Mar 4, 2026 · 9 min read
Database Scaling Strategies: Replication, Sharding, and Partitioning
A practical guide to scaling databases in system design: when to replicate, when to shard, and how partitioning strategies affect your architecture.
Mar 3, 2026 · 9 min read
Load Balancing Strategies for System Design
How to pick the right load balancing algorithm, where to place balancers, and when a single load balancer becomes the bottleneck.
Mar 2, 2026 · 8 min read
Message Queue Architecture for System Design Interviews
Understand when and how to use message queues in system design: decoupling, backpressure, delivery guarantees, and the operational patterns that matter.
Feb 20, 2026 · 7 min read
Queue-First API Design for Burst Traffic
Use synchronous API boundaries for intent capture and asynchronous queues for expensive work, retries, and operator visibility.
Feb 17, 2026 · 8 min read
Cache Invalidation That Does Not Burn Your Team
A practical pattern for choosing TTLs, write paths, and invalidation triggers without turning cache logic into a production risk.