Crack That Weekly

Build a Task Queue in Python From Scratch

Priority scheduling, worker pools, and the producer-consumer pattern behind Celery, SQS, and every background job system you have ever used

May 10 • Sharon Sahadevan

April 2026

Build a DNS Resolver in Python From Scratch

Recursive resolution, TTL caching, and the chain of responsibility pattern that powers every internet request you make

Apr 10 • Sharon Sahadevan

Build a Load Balancer in Python From Scratch

Round-robin, weighted, and least-connections — three algorithms you configure in nginx every week, now built from zero

Apr 3 • Sharon Sahadevan

March 2026

Build a Rate Limiter From Scratch in Python

Three algorithms, one deque, and the trade-off every API gateway makes — sliding window vs token bucket, explained for interviews

Mar 27 • Sharon Sahadevan

Why Redis Uses C, Not Python: The GIL Explained

Your MiniRedis has a hidden bottleneck. Understanding it is the difference between a junior and senior answer in system design interviews.

Mar 20 • Sharon Sahadevan

1

Implement TTL and Key Expiry in Python From Scratch

Two expiration strategies, one min-heap, and the clever trick Redis uses to expire millions of keys without freezing

Mar 13 • Sharon Sahadevan

Build a Key-Value Store in Go

Goroutines, RWMutex, and zero dependencies — why Go is what Redis would use if it were built today

Mar 7 • Sharon Sahadevan

2

Redis Persistence in Python: WAL & Snapshots From Scratch

Your key-value store survives restarts — using the exact same techniques Redis, PostgreSQL, and Kafka use under the hood

Mar 6 • Sharon Sahadevan

February 2026

Build Your Own Redis in Python: Key-Value Store From Scratch

Why every DevOps engineer already understands Redis internals — and how to prove it in a coding interview

Feb 28 • Sharon Sahadevan