Tokens & Context Windows

Learn what a token is, how context windows fill up, and why cost and quality both hinge on context. Free, one sitting.

25Sessions
beginnerLevel

Core competency stack

Start Learning for Free5 modules, 25 sessions below

Learning Path

25 sessions. Open a chapter to see every session, its brief, and the tools you'll use.

  • Tokens are not words

    Why text splits the way it does, and what that means for you.

  • How text becomes tokens

    Walking through tokenization on real text.

  • Code and non-English text

    Why some content costs far more tokens than others.

  • Counting tokens before you send

    Estimating size without guessing.

  • Why letter counting is hard

    A surprising weakness that falls out of tokenization.