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Lessons (40)
- Edge, Platform & Frontend Delivery
Choose rendering, middleware, caching and deployment boundaries deliberately so a frontend is fast globally, safe to release and …
- Message Delivery: Queues, Kafka, Ordering and DLQs
… prove it worked Test crash-before-offset, duplicate delivery, out-of-order versions and dead-letter replay. Measure …
- Delivery Guarantees: At-Most, At-Least & Exactly Once
Can a message be lost? Delivered twice? Learn Kafka's three delivery semantics, idempotent producers, transactions for read …
- GitOps, Progressive Delivery and Observability
… config change does not require a rebuild. Progressive delivery A rolling update replaces pods gradually, but sends real …
- Design a Reliable Notification System
… Measure urgent-message queue age, accepted delivery rate, duplicate complaints and unknown-attempt age; do not call provider …
- CloudFront: Faster Websites and Safer File Delivery
… Private customer downloads need a viewer-access design, such as CloudFront signed URLs/cookies or an authenticated delivery …
- Real-Time, Pub/Sub, Webhooks and CDC
Choose the right push or event mechanism and keep event delivery observable, idempotent and replayable. The problem in …
- Proxies, APIs and Real-Time Protocols
… These interactions have different latency and delivery needs. What must be true Choose communication by interaction semantics, including …
- The Hot SKU Alert Problem
A staff-level design exercise for notifying millions of watchers without losing delivery guarantees, flooding providers or locking …
- Train Your First Model from Scratch
… Create delivery model.py , paste the following complete program, and run python3 delivery model.py . Only Python's …
- What Is Artificial Intelligence? A Developer's Guide
… past orders + actual delivery times → learning algorithm → model Inference: new order + saved model → estimated delivery time A prediction …
- L6 Production Debugging Casebook
… See [Kafka delivery](./message-delivery-and-kafka). 3. One scheduled job on three pods Without coordination, three reports …
- Design a Chat Application
… Require no acknowledged-message loss under the declared failure model; measure delivery lag and per-conversation ordering violations …
- Terraform: Start Here
… 3. Advanced, lessons 11–15: adoption and refactoring, testing, security, automated delivery, and recovery. 4. Capstone, lesson 16 …
- Machine Learning Fundamentals
… example python Imagine a model trained on past deliveries. features = {"distance km": 8.2, "hour": 17, "rain mm …
- Python and Math Foundations with Runnable Examples
… for model experiments. Features are measurable inputs A delivery might have distance, number of items, and rain as …
- What to Learn in AI, and in What Order
… 6. Reliable delivery: Evaluate quality, protect data, address abuse and prompt injection, manage latency and cost, and monitor …
- AWS Messaging: Queues, Topics and Events
… SQS is at-least-once delivery: design workers so a duplicate message is safe. Use a message or …
- Production Capstone and Interview Practice
Combine modules, isolated environments, remote state, tests, and reviewed delivery in a production-style storage project. Build a …
- Practical Lab: S3 File Upload and CloudFront Delivery with NestJS
Build a private S3 bucket, put CloudFront in front of it with Origin Access Control, create a least …
- Backend Languages: Node.js, Go, Python & Rust
… simple to drive, very efficient, built for many deliveries at once. - Python 🚙 = a comfortable SUV: easy for everyone …
- Message Queues & RabbitMQ
… The DLQ stops it from blocking the queue forever. Delivery guarantees Guarantee Meaning How --- --- --- At most once May …
- Event-Driven Architecture
… Order received, confirming…" Duplicate events (at-least-once delivery) Idempotent consumers: store processed event IDs Ordering Partition by …
- Concurrency, Resilience & Distributed Workflows
… safe retries and duplicate delivery At-least-once delivery is the practical default for queues and webhooks. Store …
- System Design Interview Framework
… There is no stated audience, load, group size, delivery promise or retention policy. What must be true Turn …
- Networking, DNS and Traffic Routing
… application protocols run over transport (TCP/UDP), then network routing (IP), then links/physical delivery. A hostname becomes …
- 500 Users Upload Documents at Once: Design the Background Job Pipeline
… Keep the database as the truth and the queue as a delivery mechanism. If the queue is flushed …
- CI/CD and Reviewed Production Changes
… saved plans, serialization, and drift checks. A useful delivery sequence mermaid flowchart TD A[Infrastructure pull request] -- B …
- Storage, Search and Location Queries
… A user query tokenizes text, applies filters such as open-now/delivery area, ranks candidates, and returns a …
- Clean Architecture in Depth
… It calls an output boundary (a presenter), which formats the result for a specific delivery mechanism (JSON, HTML …
- Premiere-Night Video Streaming
… capacity. Keep control-plane logs separate from CDN delivery metrics. A fast API does not prove viewers are …
- How a Web Request Works
… You establish a reliable delivery route → TCP connection. 3. You put the letter in a sealed envelope → TLS …
- Developer Learning Plan and Document-Assistant Capstone
… Week 3 Training, loss, data splits Train the delivery model Compare a baseline on unseen rows Week 4 …
- JavaScript Essentials: Event Loop, Closures & this
… time Web APIs (browser) / libuv (Node) Oven, timer, delivery driver Do slow work in the background Microtask queue …
- Kafka vs RabbitMQ & the Kafka Ecosystem
… API). Key takeaways - RabbitMQ = smart routing + delete after delivery; Kafka = durable, replayable, ordered log at huge scale. - Choose …
- Kafka Producers
… They can also ask for delivery confirmation : none, "the post office received it", or "the post office and …
- Event-Driven Patterns, Step Functions and Reliable Lambdas
… If it crashes after charging but before writing, the next delivery charges again. Reversing the order can instead …
- Choosing an Architecture
… help If you most need… Consider --- --- Speed of delivery now Monolith / modular monolith, layered or vertical slices, serverless …
- 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 …
- CloudWatch: Know What Your App Is Doing
… In ECS, configure a log driver such as awslogs ; writing stdout alone does not configure CloudWatch delivery. On …