Learning paths · Free forever

Learn AI. Ship apps. Write code.

Three paths, one rule: everything here is free and everything here is real. Learn how AI works in plain words, copy the zero-dollar stack this very site runs on, or treat each lab as a coding lesson and learn by pressing Run.

Start with AI The free app stack

Path one

AI, plainly

Eight short guides that explain modern AI the way you would explain it to a smart friend: no jargon, no hype, no math degree required. Read them in order: each one builds on the last.

Your words get sliced into tokens, then the model writes an answer.

Guide 1How an LLM Works

Watch how a large language model turns a prompt into text: tokenize, read, predict, repeat.

Guide 2Tokens: The Pieces AI Reads

An LLM never reads whole words: it reads tokens. See how text gets sliced before the model reads it.

Guide 3RAG: Answers Grounded in Your Documents

Retrieval-augmented generation finds the right passages in your documents, then lets the model answer from them.

Guide 4Embeddings: Meaning as Numbers

How do computers compare the meaning of two sentences? By turning them into lists of numbers.

Guide 5AI Agent vs Chatbot

A chatbot replies; an agent works in a loop toward a goal. Watch the decide-act-observe loop.

Guide 6AI or Plain Logic? When Not to Use AI

An LLM adds uncertainty, cost, and failure modes. A decision guide for when plain code wins.

Guide 7Why AI Hallucinates

A language model predicts text, not truth. The four reasons AI invents convincing-but-wrong details.

Guide 8Prompt Anatomy: Writing Clear Prompts

A clear prompt has four parts: task, context, constraints, and format. Watch a vague prompt rebuilt piece by piece: the capstone of the path.

Every guide is a simplified educational explanation: the shape of the idea, labeled as such. Prefer watching to reading? The AI Lab animates the LLM, RAG, and agent flows step by step.

Path two

Ship apps for free

You do not need a budget to ship software. PlainLogic itself runs on free tiers: this guide shows the exact stack, what each tier really gives you, and how to handle API keys without leaking them into the browser.

Push your code and it flows to the world — on free tiers.

Guide

The free app stack

GitHub for code, a free hosting tier for deploys, free public APIs with no key, and the API-key pattern done right: with PlainLogic as the worked example. What you can build for $0, the real limits, and the signs you've outgrown free. No hype, no affiliate links.

Live proof

This site is the demo

PlainLogic deploys from a free GitHub repo to a free hosting tier on every push, and its live data comes from free public APIs. The guide points at the real pieces of this site: not a hypothetical example.

Code → push → live. That is the whole deploy pipeline.

Path three

Code with the labs

Each lab in the PlainLogic lab is a working system: and each one teaches a real skill. Open the lab, press Run, and you are studying the idea, not just reading about it.

Real data goes in, the lab works it, a result comes out. That is the lesson.

Lesson · APIs

Situation Room

Learn to work with live APIs: query weather, water, earthquake, and space-weather data, and see how a server-side proxy keeps API keys out of the browser. The flagship console: start here.

Lesson · Networking

Network Lab

Learn how the internet moves data: packets, routes, retries, and latency, animated as requests travel across a simulated network.

Lesson · ETL

Data Pipeline Lab

Learn ETL the honest way: extract raw data, transform it into something usable, load it somewhere it belongs: watch each stage fire.

Lesson · Workflows

Automation Lab

Learn workflows and automation: chains of steps that run on their own, with the triggers, conditions, and failure handling that real automation needs.

Lesson · AI systems

AI Lab

Learn how AI works: press Run on the LLM, RAG, and agent flows and watch the three ideas behind modern AI move across the diagram.

Lesson · Operations

Server Room

Learn how servers stay up: health checks, load, failover, and the monitoring that tells you something is wrong before your users do.

Honest answers

What Learn is (and is not)

Is this a course? Do I get a certificate?

No. Learn is a collection of guides and working labs, not a course platform. There are no accounts, no progress tracking, no quizzes, and no certificates: just pages you can read and labs you can run, free.

Where should a total beginner start?

With the "AI, plainly" path, in order: Guide 1 explains the one idea everything else builds on. If you want to build things instead, start with the free app stack guide: it shows what a real deployed app is made of before you write a line of code.

Are the simplified explanations honest?

The guides teach the shape of each idea and say so where they simplify. The AI Lab goes further and labels every animation a "simplified educational visualization." The goal is understanding that survives contact with the real thing, not the appearance of expertise.