Search

Lessons (40)

• Onion Architecture & Clean vs Hexagonal vs Onion

  … The application is built around an independent object model . 2. Inner layers define interfaces; outer layers implement them …

• CI/CD and Reviewed Production Changes

  Design an automated plan and apply workflow with protected credentials, saved plans, serialization, and drift checks. A useful …

• Drift, Troubleshooting, and Disaster Recovery

  Diagnose common failures, recover after partial applies, and operate state without destructive guesswork. Start with the failing layer …

• Design a Chat Application

  Deliver live messages without losing them by separating durable messages from fan-out, presence and offline notifications. The …

• 10,000 Users Do Not Need 10,000 Database Connections

  A practical mental model for connection pools, database pressure, query latency and safe scaling in Node.js applications …

• Imports, Moved Blocks, and Safe Refactoring

  … Import blocks make adoption reviewable through the plan/apply workflow. Provider docs define the import ID; different resource …

• Safe AWS Deployments with IaC and CI/CD

  Keep infrastructure in version control, review changes before applying them, and deploy applications through repeatable automated steps. Two …

• Your First Terraform Project

  … Read its filename and content before continuing. bash terraform apply first.tfplan cat welcome.txt terraform output file …

• Run Containers on AWS with ECR and ECS

  … It does not grant the eventual application S3 or database permissions. Build for the architecture configured in the …

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

  … The web application sends POST /checkout to the controller. 2. The controller turns the HTTP request into a …

• Terraform: Start Here

  Understand infrastructure as code, the plan/apply workflow, and the learning path from local experiments to team operations …

• Networking, DNS and Traffic Routing

  … The application still must set deadlines and authorization; a proxy cannot make an unsafe service safe. Failure decisions …

• Production Capstone and Interview Practice

  … Require a reviewed lock file and serialized applies. After apply, inspect bucket settings, record the resource addresses, and …

• AI Agents and Tool Use

  … The model proposes an action; application code should decide whether the action is valid and authorized. mermaid sequenceDiagram …

• Domain-Driven Design: Tactical Patterns

  … Entities, value objects, aggregates and their four rules, repositories, domain services, application services, domain events and factories, all …

• Hexagonal Architecture (Ports & Adapters)

  Put the application in the centre and plug everything else in through ports and adapters. Driving vs driven …

• O — Open/Closed Principle

  … number; } class BlackFridayDiscount implements DiscountRule { appliesTo = (cart: Cart) = isBlackFriday(new Date()); discount = (cart: Cart) = cart.total 0.3 …

• AWS Security Building Blocks

  … Cognito User Pools support application sign-in and tokens. IAM roles authorize workloads to call AWS APIs. A …

• What Is Artificial Intelligence? A Developer's Guide

  … The resulting spam detector is a machine-learning application. It still needs ordinary software to authenticate users, read …

• Design a Logging and Monitoring Platform

  … If buffers fill, apply explicit priority-based loss rather than consuming unlimited application memory. How to prove it …

• Dependencies, Data Sources, and Resource Lifecycle

  … Keep identity based on configuration, not an ID generated during apply. Replacement deserves attention A -/+ plan indicates destruction …

• Clean Architecture in Depth

  … Use case with its ports ts // src/application/ports.ts — interfaces OWNED by the application export interface OrderRepository …

• State, Remote Backends, and Locking

  … Do not use the application bucket from lesson 5 as its own backend storage. In the application root …

• Vertical Slice Architecture & the Modular Monolith

  … number }; export { getProductSnapshot } from "./application/getProductSnapshot"; // modules/ordering/application/placeOrder.ts import { getProductSnapshot } from "@/modules/catalog"; // ✅ public API …

• Secrets, Ephemeral Values, and Least Privilege

  … When applying a saved plan, ephemeral values needed during apply must be supplied again. Design runner credential renewal …

• CloudWatch: Know What Your App Is Doing

  … CloudTrail records AWS account actions, such as who changed a security group. Start with useful application logs Write …

• Domains, Load Balancers and HTTPS

  … app.example.com] -- D[Route 53 DNS] D -- A[Application Load Balancer] A -- T[Healthy app target] Route …

• Clean Architecture

  Organise an application in layers so business rules don't depend on frameworks, databases or the web. Follow …

• AWS: Start Here

  … Start by learning storage and identity, then add compute when you understand what the application needs. Follow one …

• Scaling, Load Balancing & Rate Limiting

  … Very fast, doesn't read HTTP. - L7 (application): reads HTTP, so it can route /api/ to API servers …

• Prompting and Structured Outputs

  … It can improve consistency, but it cannot guarantee correctness or replace application-side validation. A dependable prompt shape …

• GitOps, Progressive Delivery and Observability

  … Git is the source of truth Instead of running kubectl apply from laptops or CI, an in-cluster …

• IAM: Who Can Do What

  … The application still checks tenant ownership before producing an export. IAM restricts AWS access; application authorization restricts business …

• Providers and Your First AWS Resources

  … Plan destruction and review it before applying. An empty bucket can be deleted. If you uploaded objects, remove …

• SOLID at a Glance

  … would pass an object implementing an interface. - SOLID applies to modules, functions and React components too, not only …

• Python Fundamentals

  … return price (1 - percent / 100) main.py from shop.pricing import apply discount def main() - None: print(apply …

• Backend Design Scenarios

  … If the application receives 200,000 requests per second, 5% means 10,000 database requests per second. The …

• Layered (N-Tier) Architecture

  The classic way to organise an application into presentation, business and data layers. How it works, its rules …

• Pods: Where Your App Actually Runs

  … 80 bash kubectl apply -f pod.yaml kubectl get pods kubectl port-forward pod/hello 8080:80 Now …

• Internals, Upgrades, Resilience and Interview Questions

  … Argo CD ApplicationSets, a service mesh or Cilium Cluster Mesh, global DNS for failover. - Practice restores. A backup …