System Design

Animated explainers on system design.

All Caching & Performance Databases Kafka & Streaming Distributed Systems System Design Networking & Load Balancing ML & Agentic AI

System Design

Jun 10, 2026

Understanding Two Search Pipelines

Search consists of two pipelines: the indexing path, which processes documents, and the query path, which transforms user queries into ranked results.

System Design

Jun 6, 2026

Understanding Multi-Version Concurrency Control

MVCC allows multiple transactions to access different versions of a database row simultaneously, enhancing performance while ensuring consistency.

System Design

Jun 5, 2026

Understanding Database Commits

A database commit involves a structured order of operations to ensure data durability and consistency before acknowledging success.

System Design

Jun 4, 2026

WAL and Checkpoints in Databases

WAL ensures durability of writes while checkpoints improve recovery speed by limiting the replay needed after a crash.

System Design

May 31, 2026

Kubernetes Rolling Updates Explained

Rolling updates in Kubernetes ensure new pods are ready to serve traffic before being routed, preventing user errors during deployments.

System Design

May 30, 2026

Kubernetes and Node Failure Management

In Kubernetes, a node failure can initially seem alarming, but the system automatically recovers by rescheduling pods to maintain the desired state of applications.

System Design

May 29, 2026

Leader Election in Distributed Systems

When a leader in a distributed system fails, the challenge is not just recovery but achieving agreement on a new leader through candidate voting.

System Design

May 29, 2026

Monolith vs Microservices Tradeoffs

The choice between monolith and microservices hinges on tradeoffs, particularly the balance of simplicity versus complexity in scaling applications.

System Design

May 23, 2026

Leader Election in Distributed Systems

The challenge in leader election is ensuring all nodes agree on the new leader after a failure, not merely selecting another machine.

System Design

May 22, 2026

Indexes in Database Queries

Indexes improve data access paths in databases, making reads faster but increasing write costs, which necessitates careful consideration of their use.

System Design

May 22, 2026

Caching Strategies and Tradeoffs

Choosing the right caching strategy affects application performance and data consistency, with various approaches to consider based on workload and requirements.

System Design

May 20, 2026

Understanding Query Skew in Sharding

A slow shard can dominate the performance of a distributed query system, highlighting the importance of balanced data distribution and shard management.

System Design

May 18, 2026

The Complexity of Simple Writes

A user's single write action may trigger multiple downstream operations in a system, complicating consistency and overall system design.

System Design

May 11, 2026

Analytics Event Fan-Out: One Click, Seven Consumers, A Hundred Edge Cases

One user action becomes one event becomes seven downstream pipelines. The cost of that fan-out is schema evolution, lag, dedup, and per-consumer ordering.

System Design

Apr 28, 2026

Gray Failures: When the System Is Up and Broken at the Same Time

A node that returns 200s slowly is more dangerous than one that is fully down. Gray failures pass health checks, fool load balancers, and quietly poison everything that depends on them.

System Design

Apr 9, 2026

When Failover Is What Actually Causes the Outage

A region degrades, traffic shifts away, and the healthy regions collapse under the surge. Multi-region resilience is not about losing a region. It is about whether the survivors can carry the traffic.

System Design

Apr 3, 2026

Cascading Timeout Failures: Why Inverted Deadlines Multiply Load Under Stress

When timeouts grow as you go deeper into the call graph, slow downstreams keep doing work the client gave up on. Deadline propagation is the fix.

System Design

Mar 15, 2026

Token Bucket Rate Limiting: Bursts, Refills, and the Redis Trap

Token bucket allows bursts up to B and a sustained rate of R. Centralizing the bucket in Redis makes every API call a network hop, which scales until it doesn't.

System Design

Feb 28, 2026

Backpressure and Overload Control: Scale on Leading Signals, Not Lagging Ones

Retries and DLQs handle correctness. Backpressure handles survival. Without a signal from downstream, autoscaling on queue depth makes overload worse, not better.

System Design

Feb 27, 2026

SLOs and Error Budgets in Practice: Short Windows Beat Monthly Resets

An SLO is a target, an error budget is the runway. Monthly windows hide near-miss outages and create deploy freezes that ship even riskier code later.

System Design

Feb 27, 2026

Circuit Breaker Pattern: Stop Cascading Failures Cold

When a downstream service starts failing, the circuit breaker pattern stops you from taking everything else down with it. Closed, Open, Half-Open explained.

System Design

Feb 24, 2026

Retries, Timeouts, and Bulkheads: The Resilience Patterns That Only Work Together

Retries without timeouts cause storms. Timeouts without bulkheads let one slow dependency drain your pool. These patterns are a system, not a menu.

System Design

Jan 15, 2026

Redis Is Single-Threaded and Still Has Race Conditions

Single-threaded does not mean race-free. Here is why GET-then-SET breaks under concurrency, and how Lua scripts, WATCH/MULTI/EXEC, and SETNX restore correctness.

System Design

Dec 20, 2025

Why Microservices Fail: The Distributed Monolith Trap

Microservices do not fail because the pattern is wrong. They fail because teams split the code without splitting the ownership, and end up with a distributed monolith that ships slower than the original.

System Design

Dec 19, 2025

Serverless Architecture Explained: It Is Not No Architecture

Serverless does not mean architecture-free. It means your architecture moves into IAM, API Gateway, Lambda, Step Functions, and EventBridge config, where cold starts and concurrency limits are first-class constraints.

System Design

Dec 7, 2025

Access Tokens and Refresh Tokens: Why You Need Both

Access tokens are short-lived bearer credentials sent on every API call. Refresh tokens are long-lived and only ever leave storage to exchange for new access tokens. Mixing up where each one lives is how accounts get drained.

System Design

Nov 26, 2025

Web Crawler System Design: Politeness Is a Sharding Problem

A web crawler is a URL frontier, a fetcher pool, a parser, a dedup layer, and storage. The hard part is not any one component. It is enforcing per-host politeness when the crawler is sharded across many nodes.