Free coding, AI and Office tutorials

Courses

Programming

Web and programming basics to help you write your first useful programs.

Programming

• C# Advanced — Write asynchronous, concurrent and modern C#: async/await, threads, records, pattern matching, reflection, attributes, dynamic types, expression trees, dependency injection, memory management, nullable reference types, logging and HttpClient. (24 lessons)
• C# Fundamentals — Learn C# basics and build a strong foundation for .NET development. (29 lessons)
• Dart — Learn Dart, the language behind Flutter, from your first program to async code. (30 lessons)
• Go — Learn Go, the simple and fast language behind Docker and Kubernetes, from your first program to goroutines. (30 lessons)
• Java — Learn Java basics and build reliable object-oriented applications. (33 lessons)
• LINQ in C# — Learn how to filter, sort, group, and transform data with LINQ in C#. (14 lessons)
• Python — Learn Python from the first line of code, with every example runnable in the page. (27 lessons)

Web

• Angular — Build modern web apps with Angular, one component at a time. (27 lessons)
• Astro — Build fast, content-driven websites with Astro, one page at a time. (28 lessons)
• CSS — Learn how to style responsive, easy-to-use web pages with modern CSS. (26 lessons)
• Express.js — Build web servers and REST APIs with Express 5 and Node.js, one route at a time. (23 lessons)
• HTML — Learn how to structure clear, accessible web pages with modern HTML. (24 lessons)
• JavaScript — Learn JavaScript basics and create interactive experiences for the web. (31 lessons)
• Node.js — Run JavaScript outside the browser: scripts, files, servers and tools with Node.js. (17 lessons)
• React — Build fast, interactive user interfaces with React and TypeScript, one component at a time. (27 lessons)
• SCSS — Learn how variables, nesting, and mixins make CSS easier to manage. (22 lessons)
• TypeScript — Learn how TypeScript makes JavaScript safer and easier to maintain. (21 lessons)
• Vue.js — Build reactive web apps with Vue 3, TypeScript or JavaScript, one component at a time. (31 lessons)

Foundations

Databases, tools, APIs and design concepts every developer builds on.

Databases & tools

• Git — Learn how to track code changes and work safely with other developers. (25 lessons)
• Markdown — Write clean Markdown that reads well for people, renders the same everywhere, and steers AI agents, then export a Markdown kit for your own repo. (18 lessons)
• Playwright — Test real websites in Chromium, Firefox and WebKit with Playwright, in TypeScript or JavaScript, with a test lab in your browser. (23 lessons)
• Regular Expressions — Learn how to find, check, and replace text with regular expressions. (19 lessons)
• SQL — Learn how to find, combine, and update data in relational databases. (30 lessons)
• Testing & Verification — Treat every AI change as a claim. Prove it or catch it with tests that fail on wrong code, in a real test lab in your browser. (18 lessons)

Architecture

• Algorithms — Learn how to solve problems step by step, and how to tell a good algorithm from a slow one. (26 lessons)
• API — Build a real coffee-shop API in your browser: design the contract, then make it documented, versioned, secure and fast, and learn when to use GraphQL or gRPC instead. (24 lessons)
• Data Structures — Learn how to store and organize data with arrays, stacks, queues, trees and graphs. (20 lessons)
• High-Level Design — Design systems that hold up under real traffic. Write requirements, estimate load, pick components and prove each choice with a simulator, using one food delivery app from start to finish. Then design ten real systems end to end on a design canvas. (36 lessons)
• Low-Level Design — Turn a design into code that is easy to change. Learn OOP, SOLID, UML and design patterns by refactoring and building real classes, checked by hidden tests and drawn as class diagrams as you go. (16 lessons)

AI fundamentals

How language models work and how to talk to them well.

Core concepts

• Context Engineering — Learn to choose, arrange and check what an AI model sees, so its answers are correct, safe and affordable. (15 lessons)
• Large Language Models — Learn what large language models are, how they read text, and how they write replies. (19 lessons)
• Prompt Engineering — Learn to write prompts that get clear, correct and repeatable answers from AI models. (20 lessons)

AI-powered development

Let agents write code with you, safely.

Working with agents

• Agent Skills — Teach AI coding agents your team's repeatable workflows with skills, then build, test and share a DevKit of everyday developer skills. (17 lessons)
• AI Coding Agents — Use AI coding agents like Claude Code, Cursor, Copilot and Codex safely on a real codebase, from ticket to merged pull request, and see how agents work under the hood. (30 lessons)
• AI Security & Guardrails — Attack an AI feature in a safe range, then add guardrails that really hold: architecture, permissions and checks outside the model, not just prompt rules. (16 lessons)
• Graph Engineering — Decide when one loop is enough and when work needs a graph. Then design one: nodes, edges and shared state, with limits on width, depth and spend. (12 lessons)
• Harness Engineering — Build the rules, skills, hooks and checks that make an AI coding agent do the right thing every time, then export them for your own repo. (16 lessons)
• Intent Engineering — Write the intent, spec and acceptance criteria that let an AI coding agent build the right thing without guessing, then export them for your own feature. (17 lessons)
• Loop Engineering — Design a loop that finds the work, hands it to an agent, checks it, records it and knows when to stop. You stay the engineer who gives the verdict. (12 lessons)
• Model Context Protocol — Learn how AI apps connect to tools and data with MCP, then design, build and run your own servers safely. (23 lessons)

AI-powered applications

Build AI features into your own apps.

Building with AI

• AI Evals & Observability — Answer "is this AI feature good, and is it getting better or worse?" with numbers instead of vibes. Build evals, check your judge, gate releases and watch production. (16 lessons)
• Building AI Agents — Engineer production AI agents: build one support agent from the loop up, then give it tools, structured output, memory, permissions, human approval, injection defences, streaming, evals and observability. TypeScript and C# (.NET), with a simulated model, WebLLM in your browser, or Claude/OpenAI. (21 lessons)
• Fine-tuning & Model Customization — Decide when to fine-tune and when not to. Climb the customization ladder, train a LoRA adapter, read the loss curves, and own the result. (19 lessons)
• LLM Cost, Latency & Model Selection — Predict what an AI feature will cost and how fast it will feel before you ship it. Pick the right model per task, then cut cost and latency without losing quality, and prove every saving with an eval. (16 lessons)
• Multimodal AI — Build features that see, read, listen and speak: receipts, invoices, screenshots, charts, voice and video. Pick the right model, check what it extracts, and know what each choice costs. (19 lessons)
• Retrieval-Augmented Generation — Learn how AI apps answer questions from your own documents, then build, tune and evaluate a full RAG pipeline in your browser. (22 lessons)

Office Productivity

Create, edit and automate Word, Excel, PowerPoint and PDF documents, and use AI chat tools well at work.

Office tools

• Excel — Learn Microsoft Excel from the first blank sheet to formulas, charts, and real-world reports, practising every step in an Excel sandbox. (27 lessons)
• PDF — Learn to read, search, annotate, fill in, sign, and print PDF documents, practising every step in a PDF viewer sandbox. (13 lessons)
• PowerPoint — Learn Microsoft PowerPoint from the first blank slide to designed, animated, and presented decks, practising every step in a PowerPoint sandbox. (20 lessons)
• Word — Learn Microsoft Word from the first blank page to finished letters, reports, and resumes, practising every step in a Word sandbox. (25 lessons)

Artificial intelligence

• Prompting at Work — Write prompts that get a usable answer in one or two tries, check the answer before it goes out, and keep confidential data out of the chat. No coding needed. (15 lessons)

Marketing & Growth

Run paid campaigns that bring in pipeline, measure what they return, and use an LLM to review them.

Paid advertising

• Google Ads for B2B Teams — Get a small, well-tracked Google Ads Search campaign live in your first week, then learn tracking, geo bidding and budget decisions while it collects data. Advice follows your LLM, budget, goal and region. (16 lessons)