About CalibreOS
Built for the interview you actually want to ace.
Most interview prep resources teach you what to memorize. CalibreOS teaches you how to think. We built the platform we wish existed when we were going through FAANG loops — one that treats you as an engineer, not a student cramming for a standardized test.
The result is a concept library, practice suite, and quiz engine that covers DSA, System Design, Machine Learning, GenAI & Agents, and Stats — each topic written at the depth of a top-tier engineering blog, not a prep PDF.
300+
concept guides
150+
practice problems
9
library tracks
9/10
minimum content bar
What we stand for
No filler
Every guide is written to the depth of a senior engineer who has built and operated the system in production. If a sentence could have been written without domain expertise, it doesn't ship.
Production-level specifics
We cite real system names (FAISS, Triton, Kafka, LightGBM), real numbers (latency budgets, sampling ratios, scale targets), and real failure modes — not placeholder diagrams.
Interviewer-aware framing
Each topic is structured around what the interviewer is actually testing, what answer disappoints, and what answer signals senior-level thinking — not just what the algorithm is.
Free by default
Beginner-level content is free and always will be. You shouldn't need to pay to understand how a monotonic stack works or what cross-entropy loss means.
What we cover
DSA & Coding
Patterns, complexity, system-aware problem solving — beyond LeetCode grinding.
System Design
HLD, LLD, distributed systems — with latency budgets and failure modes, not vague boxes.
Machine Learning
Classical ML, deep learning, feature engineering, probability — theory + code + debugging.
ML System Design
Recommendation, ranking, search, fraud detection — end-to-end ML system walkthroughs.
GenAI & Agents
LLMs, RAG, fine-tuning, inference infrastructure, evaluation — the stack that's reshaping interviews.
Stats & A/B Testing
Hypothesis testing, causal inference, experiment design — what data-adjacent roles actually test.
Questions or feedback?
We read every message. Reach out at support@calibreos.com