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Thoughts on design, code, and everything in between.

If Your API Is Stateless, Why Do Users Keep Getting Logged Out?

The invisible session bugs hiding in plain sight. Exploring random logout issues in distributed stateless APIs, from token expiry and signing keys to load balancer failures and mobile OS eviction.

May 16, 2026•5 min read

System DesignAuthenticationDistributed SystemsJWTDevOpsDebugging

'Email Already Taken': Checking Millions of Signups at Scale

Building a robust email uniqueness check that scales to millions of signups. We'll explore Bloom filters, race conditions, email normalization, and why a simple database query isn't enough.

May 4, 2026•5 min read

System DesignDjangoDatabasesBloom FiltersDistributed SystemsPerformanceScaling

How YouTube Stores Downloaded Videos for Offline Playback: A Deep Dive

Ever wondered what actually happens when you hit 'Download' on YouTube? A full system design breakdown of how YouTube encrypts, stores, and serves offline videos on your device.

Apr 10, 2026•5 min read

System DesignYouTubeDRMMobile StorageVideo StreamingEncryptionAndroidiOS

How E-commerce Websites Actually Work: Full System Simulation with Docker

A practical walkthrough of a mini e-commerce architecture using Nginx, Node.js, PostgreSQL, Redis, RabbitMQ, and a worker service with Docker Compose.

Mar 20, 2026•5 min read

DockerE-commerceNext.jsMicroservicesPostgreSQLRedisRabbitMQ

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