Vitalii Ivanov
Senior Software Architect / Tech Lead
Here you'll find tutorials on technologies I recently found fascinating, or simply wanted to brush up on.
Tutorials
Showing all 26 tutorials
Async Python: how one thread checks 100 links
Tags:PythonCoroutines, the event loop, tasks and TaskGroup, cancellation and timeouts, semaphores and queues, blocking calls and threads, the GIL, subinterpreters and free-threaded Python 3.15, followed through one link checker and the 494 switches its single thread makes.
AWS Bedrock and SageMaker: how one support chat gets answered
Tags:AWSAIInference profiles and cross-Region routing, data residency, how Claude is hosted in AWS, GPU and accelerator instances, SageMaker AI endpoints, autoscaling, batch and PrivateLink, followed through one support chat and the $5,386 monthly bill its design adds up to.
Prometheus: how one bad deploy becomes one alert
Tags:OtherMetrics, scraping, the time series database, PromQL, alerting rules and Alertmanager, followed through one bad deploy and the 402,329 samples Prometheus stores around it, with PCA exam cues.
AWS Route 53: how one checkout resolves eight names
Tags:AWSHosted zones, alias records, routing policies, health checks and failover, the VPC Resolver, hybrid and multi-account DNS, DNS Firewall and DNSSEC, followed through one checkout and the 16 DNS queries it causes.
Kubernetes basics: what happens after kubectl apply
Tags:OtherThe API server, etcd, controllers, scheduler, kubelet, kube-proxy and CoreDNS, followed through one app on a three-node cluster and the 220 writes it causes, with KCNA exam cues.
AWS access: how one laptop reaches a private database
Tags:AWSAccess keys, session tokens, SigV4 signing, the credential chain, IAM Identity Center and Session Manager, followed through one laptop and the 21 requests it sends to AWS.
AWS KMS: how one invoice stays encrypted for seven years
Tags:AWSAWS owned, AWS managed and customer managed keys, envelope encryption, key policies, cross-account access, rotation and deletion, followed through one invoice and the 20 KMS calls made for it.
AWS VPC: how one request crosses a private network
Tags:AWSSubnets, route tables, security groups, NAT, endpoints and Transit Gateway, followed through one checkout request and the 57 checks it passes.
AI benchmarks: what the numbers actually measure
Tags:AIWhat one benchmark test looks like, who writes the tasks, who runs them, who grades the answers, and whether the model has already seen the questions.
The AI stack: how one claim crosses six layers
Tags:AILangChain, LangGraph, Langfuse, Airflow and the Claude Agent SDK: which job each one owns, shown on one insurance claim.
Diffusion models: how noise becomes a picture
Tags:AIHow a prompt and a grid of random numbers become an image, and why the network only ever predicts noise.
MCP: how one question becomes a tool call
Tags:AIHow one question travels from your editor to a tool and back: the protocol every AI client now speaks.
Claude Code: how one prompt becomes a code edit
Tags:AIWhat a coding agent actually does between your prompt and the two lines it ends up changing.
Git worktrees: how three AI agents share one repo
Tags:AIHow several agents work in the same repository at once without overwriting each other.
Interpreted vs compiled: how one line reaches the CPU
Tags:PythonOne line of code through Python, JavaScript, Java and Go, and why the split is a dial, not a dichotomy.
Reasoning models: how a model learns to think before it answers
Tags:AIWhat a model is really doing while it thinks, and why the thinking is what makes it right.
Concurrency: how Java, Node, Go & Python hold 10,000 clients
Tags:PythonFour runtimes under the same flood of connections, and the two tricks all of them rely on.
Transformers: how five words become a sixth
Tags:AIOne five-word prompt followed through GPT-2 small: tokens, embeddings, attention, 12 layers and the final scores, and the 928 million operations it takes to pick the sixth word.
LoRA: how to teach a frozen model in 8 megabytes
Tags:AIHow to teach a frozen model a new skill by training a tiny patch instead of the weights.
Prompt injection: how a poisoned email hijacks an AI assistant
Tags:AIOne email nobody opens makes an AI assistant send 512 characters of customer data to a stranger. Follow it from inbox to leak, then see which defenses bring the count back to 0.
AI evals: how a one-line prompt change earns the right to ship
Tags:AIOne line is added to a support agent’s prompt. Code checks, an LLM judge, three reviewers, 200 agent runs, statistics and a canary decide whether it ships.
AI numbers every AI engineer should know
Tags:AIThe handful of numbers that explain what a model costs, how fast it answers, and why.
AI agent patterns: how one support ticket gets closed
Tags:AIWhat an agent is made of, and every core pattern, shown on one support ticket with real code.
RAG: how one question finds its answer in 2 million words
Tags:AIOne question about the federal uniform allowance, answered from 2,034,544 words of US law: chunking, embeddings, cosine similarity, HNSW search, reranking and a cited answer, every number from one real run.
Neural networks: how three architectures read one handwritten 7
Tags:AIPixels, neurons, softmax, backpropagation, convolution and recurrence, followed through one MNIST seven and the 2,614,536 multiplications three networks spend reading it.
How a browser loads a page: from Enter to pixels
Tags:OtherOne Enter key followed for 320 ms and 132 packets: the keypress, URL parsing, DNS, TCP, TLS 1.3 with a post-quantum key share, HTTP/2, Google’s front end and the render pipeline.