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Courses · Level 3 Engineer

RAG From Scratch

Retrieval you build yourself — and then actually measure.

Available 13 chapters ~60 minutes One file, yours forever Works offline
What it is

Retrieval you build yourself — and then actually measure.

Built from scratch in the browser with no framework, so you see every moving part: meaning as geometry, real vectors and cosine similarity over a live corpus, chunking strategies you can feel the tradeoffs of — and then the chapter almost nobody teaches, where you measure whether retrieval actually helped.

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Narrated end to end

Press play and a teacher talks you through the whole build, with a read-along transcript that highlights as it speaks.

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Demos on the page

Working, offline interactives — not screenshots. When the narration says "try it", the thing is right there.

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One file forever

No account, no app, no subscription. It runs from a single HTML file and will still run in ten years.

Measured claims only

Every number is computed live on the page from inputs you can edit. Nothing is asserted that cannot be checked.

Who it is for

Written for builders whose AI needs to know their documents.

Explain embeddings as geometry, not magic

Build working retrieval end to end without a framework

Choose a chunking strategy for a specific document shape

Measure retrieval hit-rate before and after a change

Inside

13 chapters, the first four free

The free preview is not a teaser: those chapters are complete, and the paid chapters are physically absent from the preview file rather than hidden behind a script.

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Welcome — and the live demo

What this hour is, how to use the page, and the interactive demo you will keep coming back to.

FREE
01
Chapter 1

Part of the free preview — the full narration, page content and exercises, nothing held back.

FREE
02
Chapter 2

Part of the free preview — the full narration, page content and exercises, nothing held back.

FREE
03
Chapter 3

Part of the free preview — the full narration, page content and exercises, nothing held back.

FREE
04
Chapter 4

Narrated in full, with the on-page build and exercises for this idea.

PAID
05
Chapter 5

Narrated in full, with the on-page build and exercises for this idea.

PAID
06
Chapter 6

Narrated in full, with the on-page build and exercises for this idea.

PAID
07
Chapter 7

Narrated in full, with the on-page build and exercises for this idea.

PAID
08
Chapter 8

Narrated in full, with the on-page build and exercises for this idea.

PAID
09
Chapter 9

Narrated in full, with the on-page build and exercises for this idea.

PAID
10
Chapter 10

Narrated in full, with the on-page build and exercises for this idea.

PAID
11
Chapter 11

Narrated in full, with the on-page build and exercises for this idea.

PAID
12
Chapter 12

Narrated in full, with the on-page build and exercises for this idea.

PAID