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Lessons (40)

• Code Profiling

  … Learn a repeatable profiling workflow for CPU, memory, I/O and real user requests. The big idea Profiling …

• Providers and Your First AWS Resources

  … Never paste access keys into provider blocks. bash export AWS PROFILE=learning aws sso login --profile learning aws …

• Database Relations & Foreign Keys

  … use it only when it earns its place A profile table can separate sensitive or rarely-used data …

• IAM Deep Dive: Policy Evaluation, STS and Cross-Account Access

  … Configure a local role profile and verify the resulting caller identity before testing access. AWS evaluates cross-account …

• AWS: Start Here

  … Install AWS CLI v2, then configure a named profile: bash aws configure sso --profile academy aws sso login …

• S3: Store Files Safely

  … lab/sample.txt \ --profile academy aws s3 ls s3://REPLACE WITH YOUR BUCKET/lab/ --profile academy aws s3 …

• Atomic Design & Component Libraries

  … export default async function ProfileSettingsPage() { const profile = await getProfile(); return <SettingsTemplate navigation={<SettingsNav / } <ProfileForm profile={profile} / </SettingsTemplate ; } Document …

• Go Concurrency: Goroutines, Channels and Context

  … orders, Profile: profile}, nil } Context rules: pass it as the first parameter named ctx ; never store it in …

• Safe AWS Deployments with IaC and CI/CD

  … cloudformation validate-template \ --template-body file://storage.yaml --profile academy aws cloudformation create-change-set \ --stack-name academy …

• Cross-Service Data: How to Join Without a Database JOIN

  … a profile update commits in User Service first, and the Order Service projection catches up shortly afterward. Option …

• AWS Messaging: Queues, Topics and Events

  … Use AWS CLI v2 and an authorized profile. Retrieve the queue URL through the console or get-queue …

• React Internals & Concurrent Rendering

  … changes. A render is not automatically a problem. Profile first, then reduce only expensive or user-visible work …

• RBAC and Cluster Security

  … in Pod Security Admission enforces three profiles per namespace through labels: Profile Meaning --- --- privileged Unrestricted baseline Blocks known …

• DRY: Don't Repeat Yourself

  … participant A as signup.js participant B as profile.js participant C as admin.js Note over A …

• IAM: Who Can Do What

  … caller-identity --profile academy aws s3api list-objects-v2 \ --bucket academy-shop-uploads --prefix receipts/ --profile academy aws …

• Replication, Partitioning & Sharding

  … After a profile update, reading a replica may show the old value. Use read-your-own-write routing …

• Backend Design Scenarios

  … A user updates their profile, refreshes the page and sees old data. Where did it come from and …

• REST vs GraphQL vs gRPC

  … The client sends a query describing the exact shape it wants: graphql query ProfileScreen { user(id: 42) { name …

• DynamoDB Modeling, RDS Scaling and Data Resilience

  … related items together: PK SK Data --- --- --- CUSTOMER 42 PROFILE name, email CUSTOMER 42 ORDER 2025-03-01 9001 …

• Frontend Performance & Core Web Vitals

  … end 💡 Measure before optimising. Use the React DevTools Profiler to find components that actually render slowly. Guessing leads …

• CloudFront: Faster Websites and Safer File Delivery

  … Distribution deployment and deletion are not instantaneous. Practice: a customer's profile appears in another customer's response …

• Run Containers on AWS with ECR and ECS

  … The commands below assume AWS CLI v2, Docker, an authorized academy profile, Region ap-southeast-1 , and that …

• EC2, Storage and Auto Scaling

  … An instance profile connects an IAM role to the instance so software can obtain temporary credentials. Start with …

• Proxies, APIs and Real-Time Protocols

  … log. Pick from the user interaction A “save profile” request needs one answer now: HTTP REST is a …

• API Contracts, Gateways and Security

  … for example, an attacker changing a bank recipient is more important than a cosmetic profile-field error.

• Storage, Search and Location Queries

  … ask to upload profile-photo.jpg API - Client: short-lived, scoped presigned upload URL Client - Object storage: upload …

• KISS: Keep It Simple, Stupid

  … Gateway] -- MS1[User service] & MS2[Auth service] & MS3[Profile service] MS1 -- K[(Kafka)] -- MS2 MS3 -- R[(Redis)] end …

• What Is Apache Kafka?

  … They had dozens of systems that all needed the same data (page views, profile updates, messages), and point …

• Monolith vs Microservices

  … very different scaling needs (video transcoding vs user profiles). - Parts that need different release speeds or different technology …

• State Management (Redux, Zustand, TanStack Query)

  … Zustand , Redux Toolkit Server state Products, orders, user profiles from the API TanStack Query , SWR, RTK Query URL …

• SQL vs NoSQL Databases

  … Example --- --- --- --- Document A folder of JSON files Catalogs, profiles, CMS content MongoDB Key-value A giant hash map …

• TypeScript Essentials

  … Pick<User, "id" \ "name" Only those fields Public profile Omit<User, "password" Everything except those API response Record …

• Topics, Partitions & Offsets

  … b@new.com"] end Before -- After bash kafka-configs.sh --alter --entity-type topics --entity-name user-profiles …

• Choosing a Programming Language

  … debug, profile, deploy and hire for. Raw benchmark speed is rarely the bottleneck; the database and the network …

• Scaling, Load Balancing & Rate Limiting

  … After a user updates their profile, read their profile from the primary ("read your own writes"). Sharding (partitioning …

• Practical Project: Deploy a Real CRM App on EKS

  … configure sso one-time profile setup aws sso login --profile dev export AWS PROFILE=dev aws sts get …

• Containers at Scale: ECS Deep Dive and EKS

  … API server, etcd] end subgraph Your account MNG[Managed node groups] KP[Karpenter nodes] FG[Fargate profiles] end …

• Caching & Redis

  … Short negative caching, as above, or a Bloom filter helps. Hot key: one key (a celebrity's profile …

• L6 Production Debugging Casebook

  … Compare dominator trees, retained size and growth by class; keep GC logs, allocation profiling/JFR, container memory limits …

• Practical Lab: S3 File Upload and CloudFront Delivery with NestJS

  … attach --- --- ECS or Fargate Task role EC2 Instance profile (role) EKS Pod Identity or IRSA role Lambda Execution …