Skill Gap Roadmap — Backend Engineering, System Design, AI Engineering

1. 01

   Node.js behavior you forgot

   Start with the backend concepts most directly tied to your weak spots so event-driven behavior and core runtime terminology come back quickly.

   4 topics

   • Node.js Architectureintermediate
   • Events & EventEmitterintermediate
   • File System & Processbeginner
   • Streams & Buffersadvanced
2. 02

   Backend API foundations

   Refresh the HTTP and API-building basics that support later system design and production discussions.

   5 topics

   • HTTP Fundamentalsbeginner
   • Express & Fastifybeginner
   • Middleware Patternsintermediate
   • Validation & Error Handlingintermediate
   • CRUD API End-to-Endintermediate
3. 03

   State, persistence, and performance basics

   Rebuild the database vocabulary and tradeoffs you’ll need for backend interviews and design conversations without overdoing areas you already know.

   7 topics

   • SQL Fundamentalsbeginner
   • Relational Data Modelingintermediate
   • Transactions & ACIDadvanced
   • Indexing & Query Performanceadvanced
   • MongoDB & Document Modelingintermediate
   • ORMs & Query Buildersintermediate
4. 04

   Backend reliability and production habits

   Cover the production concerns that commonly show up in backend interviews and help connect systems thinking to real services.

   4 topics

   • Testing Backend Servicesintermediate
   • Logging & Monitoringintermediate
   • Debugging Production Nodeadvanced
   • 12-Factor & Configurationintermediate
5. 05

   System design foundations

   Reinforce the core interview language and estimation framework early so the rest of system design topics fit into a consistent mental model.

   4 topics

   • Scalability Fundamentalsintermediate
   • Back-of-Envelope Estimationintermediate
   • CAP & Consistency Modelsadvanced
   • The Interview Frameworkintermediate
6. 06

   Traffic, storage, and data distribution

   These are the essential building blocks behind most backend system design questions and should come before the case studies.

   7 topics

   • DNS, CDN & Edgeintermediate
   • Load Balancingintermediate
   • Proxies & API Gatewaysintermediate
   • SQL vs NoSQLintermediate
   • Replicationadvanced
   • Sharding & Partitioningadvanced
7. 07

   Events and distributed reliability

   Focus on the event-driven and messaging ideas you explicitly called out, since they’re a weak spot and central to modern backend design.

   4 topics

   • Queues & Pub/Subintermediate
   • Event-Driven Architectureadvanced
   • Idempotency & Reliable Deliveryadvanced
   • Rate Limiting & Load Sheddingadvanced
8. 08

   Architecture patterns at scale

   Move from components to larger shapes of systems so you can discuss tradeoffs clearly in interview scenarios.

   5 topics

   • Monolith vs Microservicesadvanced
   • Serverless & Edge Architecturesintermediate
   • Observability & Security in Designadvanced
   • Multi-region Architecturesadvanced
   • Cell-based Architectureadvanced
9. 09

   Design case studies for practice

   Practice a small set of representative designs that exercise the earlier concepts without spreading attention too thin.

   6 topics

   • Design a URL Shortenerintermediate
   • Design a Rate Limiterintermediate
   • Design a Chat Systemadvanced
   • Design a Notification Systemadvanced
   • Design File Storage (Dropbox)advanced
   • Design an LLM Chat Productadvanced
10. 10

    AI engineering essentials

    Begin the AI track with the minimum concepts needed to integrate LLMs confidently into backend products.

    7 topics

    • How LLMs Workbeginner
    • The LLM Landscapebeginner
    • Prompt Engineeringbeginner
    • LLM API Fundamentalsbeginner
    • Structured Outputintermediate
    • Tool Use / Function Callingintermediate
11. 11

    Retrieval and RAG

    RAG is the most practical AI integration pattern for backend engineers, so it deserves a focused study block.

    6 topics

    • Embeddingsintermediate
    • Chunking Strategiesintermediate
    • Vector Databasesintermediate
    • Search Relevanceadvanced
    • RAG Pipelineintermediate
    • Evaluating RAGadvanced
12. 12

    AI agents and production readiness

    Finish with agent patterns, cost/safety, and operational topics so your AI knowledge is usable in real systems and interviews.

    7 topics

    • Agent Fundamentalsintermediate
    • Agent Patternsadvanced
    • Model Context Protocol (MCP)intermediate
    • Cost & Latency Optimizationadvanced
    • Safety & Guardrailsadvanced
    • AI Observabilityintermediate

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