by Amit Shekhar · 6 August 2026
Encoder vs Decoder in Transformers
Encoder vs Decoder in Transformers, the two building blocks behind almost every modern AI model that works with language. We will also see how the Encoder and the Decoder differ from each other, how each one works with simple examples, why one of them reads in both directions while the other one looks only backward, what the three types of Transformers are, and when to use which one.
Read on Outcome School ↗then come back to lock it in
Before you read, guessHow does the encoder process input to achieve deep understanding?
Ten seconds, a guess, then read — a wrong guess still makes the answer stick.
What this article covers
- What is a Transformer?
- A word about tokens
- What is an Encoder?
- What is a Decoder?
- The one big difference
- The three types of Transformers
- Let's tabulate the difference
- When to use which one?
- Summary
The article lives on outcomeschool.com. Read it there, then come back: the tutor in the margin has read it and will answer questions, and the questions below check what stayed.