Interview Prep DevNinja
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Roadmaps

Learning paths by role

Backend, AI, Data, DevOps, and Staff/Principal — prerequisites and what to do next.

Difficulty Guide Read ~12 min Master path-dependent Levels Junior → Principal

These paths are interview roadmaps, not documentation tours. Each stop links to lab questions and book chapters. Do the labs aloud on a timer.

Backend Engineer

Difficulty Medium→Hard Read ~0 min Master 8–12 weeks Levels Mid–Senior
  1. Coding patterns: Coding Lab Q1–Q20 (timed).
  2. Fundamentals: Scaling, Caching, SQL/NoSQL, Queues.
  3. Design drills: System Design Lab Q1, Q3, Q4, Q7, Q9, Q13, Q16.
  4. Comparisons: Kafka vs RabbitMQ, Redis vs Memcached, REST vs GraphQL.
  5. Behavioral: STAR + leadership stories.

AI Engineer

Difficulty Hard Read ~0 min Master 6–10 weeks Levels Mid–Staff
  1. Core book: LLMs → RAG → Agents → MCP.
  2. Lab: AI Lab all Q1–Q17 (especially Q1, Q3, Q4, Q11, Q12, Q16).
  3. Serving & cost: Q8, Q11, Q13.
  4. Eval & shipping: Q3, Q17.
  5. Optional coding: sliding window + graphs for general screens.

Data Engineer

Difficulty Medium→Hard Read ~0 min Master 6–10 weeks Levels Mid–Senior
  1. Queues & logs: Queues, SD Lab Q16 Kafka.
  2. Storage: SQL/NoSQL, Replication, SD KV store.
  3. Batch/stream tradeoffs; feature store AI Lab Q15.
  4. Coding: arrays, heaps, sorting intervals for screens.

DevOps / Platform

Difficulty Medium→Hard Read ~0 min Master 6–10 weeks Levels Mid–Staff
  1. Scaling & LB: Scaling, rate limiter SD Q4.
  2. Caching CDN: Caching, SD Q9.
  3. Observability, degradations, backpressure (SD scaling drills).
  4. AI gateway quotas if platform-for-AI: AI Lab Q8, Q11.

Staff / Principal Engineer

Difficulty Staff→Principal Read ~0 min Master ongoing Levels Staff–Principal
  1. Every SD answer must include failure modes, org interfaces, and migration plans.
  2. Deep labs: payments Q13, KV Q15, feed Q2, video Q6, RAG platform Q1+Q8+Q11.
  3. Write comparison tradeoffs from Comparisons without notes.
  4. Behavioral: conflict, influence without authority, technical strategy — Behavioral lab.
  5. Teach: explain a design to a junior in 10 minutes (interviewers test this).

How to use levels on each question

Open any Interview Lab card: use Level expectations to self-score. Junior = correct solution; Mid = clean + follow-ups; Senior = production examples + tradeoffs; Staff = platform/org impact; Principal = multi-year strategy and risk.