Fundamental Concepts of Software Systems Engineering (Step-by-Step)
From full-stack → Next.js → system design → microservices → ML → agents → production AI product.
STEP 1 — Build the Base Web Product (React + Flask + DB)
(Weeks 1–2) Your very first foundation: a real app that everything else builds on.
- Frontend (React fundamentals): JSX, Hooks, Controlled forms, Client-side routing, Context API, Data fetching.
- Backend (Flask): REST endpoints, Request validation, SQLAlchemy ORM, Auth, Error handling, DB design.
- Testing: React Testing Library, Pytest.
- Deployment: Vercel (Frontend), Render/Heroku (Backend).
- Deliverable: User + Posts + Comments product built on React + Flask + Postgres.
STEP 1.5 — Upgrade to Next.js (Full-Stack React + SSR/ISR/Edge)
(Week 2.5) Transform your React SPA into a scalable, high-performance Next.js app.
- Concepts: App Router, Server vs Client Components, SSR/SSG/ISR, API routes, Edge middleware, Image optimization.
- Integration: Auth pages (SSR), User profiles (ISR), Feed (Client + Streaming), API proxy.
- Deliverable: Next.js frontend + Flask backend.
STEP 2 — Add Architecture Fundamentals
(Week 3) Architect your existing app like a senior engineer.
- Analysis: Latency heatmap, Scalability constraints, Caching opportunities, Database bottlenecks.
- Deliverable: Architecture document (UML, Request flows, Caching plan, Scaling plan).
STEP 3 — Add Classic Distributed System Building Blocks
(Week 4) Extend your platform from "web app" to "distributed system".
- Caching Layer (Redis): Cache-aside pattern, Session storage, Rate limiting.
- Async Workers (Celery/BullMQ): Offload heavy tasks (e.g., image resizing, email sending).
- Load Balancing: Nginx basics, Round-robin vs Least connections.
- Deliverable: App with Redis caching and background workers.
STEP 4 — Add Search & Analytics (Elasticsearch + ClickHouse)
(Week 5) Handle data at scale.
- Search Engine: Indexing data in Elasticsearch, Fuzzy search, Faceted search.
- Analytics: Tracking user events, ClickHouse for OLAP, Building a dashboard.
- Deliverable: Search bar with autocomplete + Admin analytics dashboard.
STEP 5 — Add Machine Learning (The "AI" in AI Engineering)
(Week 6) Integrate a predictive model (non-LLM) into your system.
- Model Building: Scikit-learn basics, Training a simple recommender or classifier.
- Model Serving: ONNX runtime, FastAPI for inference, Batch vs Real-time inference.
- Integration: Show recommended posts in the feed.
- Deliverable: "Recommended for you" widget powered by a real ML model.
STEP 6 — Add Generative AI (LLMs & RAG)
(Week 7) The modern AI stack.
- LLM Integration: OpenAI API / Anthropic API, Prompt engineering, Streaming responses.
- RAG Pipeline: Vector DB (Pinecone/Weaviate), Embeddings, Retrieval, Context injection.
- Feature: "Chat with your posts" or "AI Summary" button.
- Deliverable: GenAI feature live in production.
STEP 7 — Add AI Agents
(Week 8) From passive chatbot to active agent.
- Agent Architecture: Tools (Search, Calculator, DB access), Planning (ReAct), Memory.
- Frameworks: LangChain / LangGraph basics.
- Feature: "Personal Assistant" that can search your posts and draft replies.
- Deliverable: Agent capable of multi-step reasoning.
STEP 8 — Production Readiness (DevOps & MLOps)
(Week 9) Make it robust, observable, and scalable.
- CI/CD: GitHub Actions pipelines for test & deploy.
- Observability: Logging (ELK/Loki), Metrics (Prometheus/Grafana), Tracing (OpenTelemetry).
- MLOps: Model versioning, Eval pipelines, Drift detection.
- Deliverable: Fully instrumented production system.