Tutorials
Step-by-step series for learning by building, one chapter at a time — pick a series below and work through its chapters in order.
New here? Follow the Start Here roadmapFoundations
The first steps every developer needs, whatever field you choose next.
How Computers Work
CPU, RAM vs storage, files, processes, threads, and what the operating system actually does — the ground every other tutorial stands on.
10 Chapters
BeginnerCommand Line Basics
Move around files, run programs, chain commands together, and stop being afraid of the terminal — every other tutorial assumes this.
11 Chapters
BeginnerGit & GitHub for Beginners
Save your work, undo mistakes, use branches, fix merge conflicts, and collaborate with pull requests — the first tool every company expects you to know.
11 Chapters
BeginnerHow the Web Works
URLs, DNS, HTTP, status codes, cookies, and caching — what actually happens between typing an address and seeing a page, traced with your browser's DevTools and curl.
11 Chapters
BeginnerHTML & CSS Fundamentals
Structure a page with semantic HTML, style it with CSS, and make it look good on phones with the box model, Flexbox, Grid, and responsive design — then publish it.
11 Chapters
BeginnerJavaScript & TypeScript Fundamentals
Learn variables, functions, arrays and objects, the DOM, async code, and then add TypeScript types — and use them to make a profile page interactive.
12 Chapters
BeginnerMath for Programmers
Binary and hex, bitwise flags, boolean logic, sets, modulo, Big-O, counting, probability, and geometry — the everyday math hiding inside your code, learned by building a small toolkit.
12 Chapters
IntermediateData Structures & Algorithms
Arrays, hash maps, linked lists, stacks, queues, recursion, searching, sorting, trees, heaps, graphs, and dynamic programming in TypeScript — tied to where you meet them at work, and ready for technical interviews.
14 Chapters
BeginnerSQL & Relational Databases
Tables, keys, relationships, JOINs, aggregation, normalization, indexes, and transactions in PostgreSQL — learned by building the database of a small online shop.
12 Chapters
Backend & DevOps
Build APIs, secure them, take payments, and ship them to production.
NestJS Crash Course
Build a Task Management REST API in 1 hour with NestJS, PostgreSQL, and Prisma.
9 Chapters
BeginnerDocker CLI Tutorial
Learn Docker from the CLI up — images, containers, volumes, networking, Compose, and shipping a real multi-container app to production.
21 Chapters
IntermediateABA PayWay Tutorial
A step-by-step, end-to-end guide to integrating ABA PayWay — the checkout flow, verifying payments, callbacks, refunds, and what going live actually involves.
7 Chapters
IntermediateBakong KHQR Tutorial
Generate a Cambodian Bakong KHQR code, render it as a scannable image, and poll for payment.
4 Chapters
BeginnerCloud+ Tutorial
A beginner-friendly walkthrough of Sabay's Cloud+ business services (SabayTEKH PaaS) — deploying a container with Run App, storing files with S3-compatible Storage, and running a managed Database with backups.
10 Chapters
IntermediateKeycloak Crash Course
OAuth 2.0, OpenID Connect, and JWTs in about an hour — run Keycloak locally, build a realm and client by hand, decode a real access token, and protect a NestJS API with it.
8 Chapters
AI
Build real features on top of large language models — chatbots, RAG, and agents.
Docker Sandboxes Crash Course
Isolated dev environments in 1 hour, then a deeper dive into AI agent sandboxing — kits, environment files, the MCP gateway, and multi-agent workflows.
13 Chapters
BeginnerHow LLMs Work (for Developers)
Tokens, probabilities, temperature, training, embeddings, context windows, prompts, and hallucinations — how large language models really work, learned by building a tiny one yourself.
10 Chapters
BeginnerBuild a Chatbot with an LLM API
Call a language model over HTTP, keep conversation memory, stream the reply, protect your API key behind a backend, handle errors and cost, and ship a web chat UI — built step by step with Node.js.
8 Chapters
IntermediateRAG: Chat with Your Own Documents
Make a language model answer from your own files: split documents into chunks, turn them into embeddings, search by meaning, build a grounded prompt with citations, improve retrieval, and measure whether it works.
8 Chapters
IntermediateAI Agents with Tools & MCP
Let a language model call your functions to get real work done: tool calling, the agent loop, well-designed tools, memory and planning, the Model Context Protocol (MCP), and the safety rules that keep an agent from doing harm.
11 Chapters
IntermediateMath for AI
Vectors, dot products, matrices, derivatives, gradient descent, probability, and a tiny neural network that learns — the intuition behind embeddings and training, learned by building a small toolkit instead of reading proofs.
8 Chapters