The library
Core explainers are free to watch. New ones land every week.
Networking
VPC design: multi-AZ with private endpoints
See a load balancer spread requests across two availability zones, private apps reach S3 without the internet, and a whole zone fail without an outage.
What a CDN actually does
Follow a request to the nearest edge location, through the regional cache, back to the origin and home again.
How DNS finds a website
Follow a lookup from the browser to the resolver, root, .com and authoritative servers, then on to the website.
VPC basics: public and private subnets
See how traffic gets into a private app through a public load balancer, and how the app reaches out through a NAT gateway.
Compute
AWS 3-tier request flow
Follow a request from the browser through the load balancer, web tier and app tier to the database and back.
A serverless API, request by request
Follow an API call through the gateway, an authorizer, a Lambda function and a DynamoDB table, with nothing to patch.
Data
AI and RAG
Production RAG with evaluation
Follow a question through a semantic cache, keyword and vector search, a reranker, the LLM and guardrails, then see how feedback drives evaluation.
RAG pipeline, end to end
Follow a question as it becomes a vector, finds the right document chunks and grounds the model’s answer.
System design
Active-active multi-region
Watch two regions serve users at the same time, replicate writes both ways, settle a conflicting write and absorb a regional outage.
Event-driven order pipeline
Follow one “order placed” event as it fans out to payments, shipping and email, survives a flash sale, and shrugs off a duplicate delivery.
Multi-region failover
Watch DNS health checks move traffic to a standby region when the primary goes dark, with data already replicated.
Queues that absorb a traffic spike
Watch orders land in a queue instantly, get processed at a steady pace, and survive a slow or broken worker.