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Lessons (40)

• Normalization & Denormalization

  … We will normalize one deliberately bad order table: order id customer name customer email product id product name …

• Putting AI Systems into Production

  Design dependable model integrations with fallbacks, observability, versioning, cost controls, and human review. The big idea A production …

• Next.js Rendering: CSR, SSR, SSG, ISR & Server Components

  … GET /products S-- B: empty HTML + bundle.js Note over B: ⬜ blank screen B- B: download + run JavaScript …

• The Hot SKU Alert Problem

  … The watch relationship remains separate from the product row. A price update changes one product record; it does …

• Caching & Redis

  … SET product:42 (expires in 300 s) end js async function getProduct(id) { const key = product:${id} ; const …

• Product-Scale Frontend Patterns

  … a server-authoritative result. Offline-first is a product decision Offline support needs more than caching assets. Decide …

• CI/CD and Reviewed Production Changes

  … Tests using apply can create resources, so isolate them from production permissions. Apply the approved artifact A protected …

• Releases, Observability and Production Safety

  Ship changes safely with rollout strategy, flags, migration discipline, rollback plans and observable service-level outcomes. The problem …

• React Fundamentals

  … cart, products"] -- products, onAdd PL[ProductList] PL -- name, price, onAdd PC1[ProductCard] PL -- name, price, onAdd PC2[ProductCard …

• Atomic Design & Component Libraries

  … shared UI stays independent of product domains; feature code stays close to its use case. Templates make loading …

• Production Capstone and Interview Practice

  Combine modules, isolated environments, remote state, tests, and reviewed delivery in a production-style storage project. Build a …

• State Management (Redux, Zustand, TanStack Query)

  … useQuery(["products"]) B- Q: useQuery(["products"]) Q- API: ONE request (deduplicated) API-- Q: data Q-- A: data Q …

• MVC, MVP & MVVM

  … routes/products.js (Express) router.get("/products/:id", async (req, res) = { const product = await Product.findById(req.params …

• Caching, Consistent Hashing and Sharding

  … Cache product reads with a defined freshness bound and coalesce concurrent cache misses. 2. Use consistent hashing to …

• How a Web Request Works

  … GET /products/42 LB- S: forward to a healthy server S- DB: SELECT FROM products WHERE id = 42 …

• Environments, Workspaces, and Multiple Accounts

  Separate development and production ownership, understand workspace limits, and configure provider aliases. Isolation has several layers Development and …

• Finding Service Boundaries with DDD

  … If one giant Product class tries to serve everyone, every team edits it, it grows to 80 fields …

• L6 Production Debugging Casebook

  Ten practical production incidents: investigate the evidence, identify the real cause and make the system safer. How to …

• Safe AWS Deployments with IaC and CI/CD

  … Continuous delivery produces reviewed deployable releases; whether production deploys automatically depends on your team's approval policy. A …

• Design System Operations

  Run a component library as a reliable product with headless primitives, theming, documentation, visual checks and a safe …

• Your Practical Kubernetes Workflow

  … shop-api 1 -n production Use helm template or helm diff before a production change so you can …

• Frontend Testing Strategy

  … 201 })), ]; tsx it("lists products from the API", async () = { render(<ProductsPage / ); expect(await screen.findByText("Keyboard")).toBeInTheDocument(); // findBy …

• SQL vs NoSQL Databases

  … 17, name: "Ana", email: "ana@mail.com" }, items: [ { productId: 5, name: "Keyboard", qty: 1, priceCents: 4999 }, { productId: 9 …

• Vertical Slice Architecture & the Modular Monolith

  … ts │ └── ProductService.ts │ │ └── handler.test.ts ├── repositories/ │ ├── cancel-order/ │ ├── OrderRepository.ts │ └── get-order-history/ │ └── ProductRepository.ts └── products/ └── dtos …

• Scalable Frontend Architecture

  Structure a growing frontend around features, clear ownership and stable boundaries so teams can add product work without …

• Indexes, EXPLAIN & Query Plans

  Design indexes from real filter, join and sort patterns, then prove improvements with query plans and production-like …

• Deploying & Operating Microservices

  CI/CD per service, blue-green and canary releases, feature flags, API versioning, distributed tracing and the production …

• Python and Math Foundations with Runnable Examples

  … The dot product multiplies matching components and adds them; the bias supplies an offset. Normalize using training data …

• Architecture Patterns at Scale

  … Style Good fit Main cost --- --- --- Client-server Most products starting out Central service capacity Microservices Independent domain ownership …

• What to Learn in AI, and in What Order

  A practical map from programming and data basics through machine learning, deep learning, LLM applications, evaluation, and production …

• Testing, Preconditions, and Policy Checks

  … Explain why passing tests still requires reviewing replacements in a real production plan. Further reading: [Terraform tests](https …

• System Design Interview Framework

  … In a hypothetical interview, results are proposed validation criteria, not invented production achievements. Check your understanding Practice a …

• Database Relations & Foreign Keys

  … Add an index on orders(customer id) when the product frequently loads a customer orders. A foreign key …

• Domain-Driven Design: Tactical Patterns

  … CustomerId) { return new Order(id, customerId); } addLine(productId: ProductId, quantity: number, unitPrice: Money) { this.assertDraft(); if (quantity <= 0 …

• Configuration, Secrets and Storage

  … Do not build separate images containing “development database” or “production database.” Put environment-specific settings outside the image …

• Python Fundamentals

  … return round(self.price 1.2, 2) p = Product("Mug", 10.0) print(p) Product(name='Mug', price …

• Containers at Scale: ECS Deep Dive and EKS

  Deploy ECS safely, scale it properly, compare it with EKS, and apply the production patterns for each. ECS …

• Concurrency, Resilience & Distributed Workflows

  … A production job should have: - a durable queue and a unique job ID; - a visibility timeout or lease …

• Design a Polite Web Crawler

  … normalize, deduplicate and schedule per host. The problem in context A search product wants to crawl 100 million …

• C4 Architecture Diagrams: Context, Container, Component and Code

  … Customers browse products and place orders. Staff manage products. The shop charges cards through Stripe and sends receipts …