Behavioral and technical interview prep for software engineers ready to take their careers to the next level.
113 posts
AISeptember 17, 2026by Formation
Prompt prefix caching reuses identical leading tokens; semantic response caching can substitute an answer for a merely similar question. Learn the validity checks, cost model, and routing tradeoffs behind each.
AISeptember 14, 2026by Formation
LLM inference splits into compute-heavy prefill and memory-bandwidth-sensitive decode. Learn why batching helps, how long prompts disrupt streaming, and which latency metrics to measure.
Interview PreparationSeptember 10, 2026by Formation
In a vector database system design interview, focus on chunk policy, metadata, filtered search, and rebuild strategy—not just the store you name.
AISeptember 9, 2026by Formation
Learn how to design a RAG system for interviews by separating retrieval from generation, with distinct freshness, latency, failure, and quality decisions.
Interview PreparationAugust 26, 2026by Formation
When an AI assistant can write working code in seconds, interviewers stop testing typing speed and start testing whether you can clarify requirements, own the design, and verify what the model produced.
Interview PreparationAugust 25, 2026by Formation
When interviewers ask you to design an AI-powered feature, they're testing system design judgment, not ML knowledge — this post shows how to treat the model as an unreliable dependency and reason about its latency, cost, and failure modes.
Engineering ResourcesAugust 18, 2026by Formation
Failover isn't just "promote a follower" — done carelessly, it produces split-brain and zombie-leader failures worse than the outage it was meant to prevent. Here's what fencing tokens, quorum election, and STONITH actually protect against.
Engineering ResourcesAugust 18, 2026by Formation
Read replicas add read capacity and failover copies, but every write still funnels through one leader—so replicas alone won't fix a write bottleneck or guarantee fresh reads.
Interview PreparationAugust 18, 2026by Formation
Most CAP theorem explanations conflate availability with freshness, CAP consistency with ACID consistency, and treat CP/AP as permanent labels. Here's how to state the trade-off correctly during a network partition.
Engineering ResourcesAugust 10, 2026by Formation
Holding a million WebSocket connections is easy; delivering one message to users scattered across servers is the hard part. Here's why a broker alone doesn't solve fanout, and what a presence registry actually buys you.
