Comparison
Decoder vs Encoder
Decoder and Encoder are both common AI/LLM terms but cover different ideas. Here is a quick side-by-side.
When you would reach for Decoder
Decoder comes up when the question is fundamentally about architecture.
GPT-4 generating a paragraph token by token.
When you would reach for Encoder
Encoder comes up when the question is fundamentally about architecture.
BERT classifying a sentence as positive or negative.
Frequently asked
What is the difference between Decoder and Encoder?
Decoder: A decoder is a transformer module that generates a sequence one token at a time, using causal self-attention so each token only sees earlier ones. GPT-style LLMs are decoder-only. Encoder: An encoder is a transformer module that reads an input sequence and produces a contextualized representation — a vector per token that captures meaning in context.
When should I use Decoder vs Encoder?
Decoder is the right concept when you are focused on architecture. Encoder applies when you are focused on architecture.
Are Decoder and Encoder the same thing?
No. Decoder is architecture; Encoder is architecture. They are related but address different parts of the AI stack.