Definition
Plain language
A speed trick where a small draft model proposes several tokens at once and a big model verifies them in parallel.
As stated in the literature
An inference acceleration technique where a draft model proposes a sequence of tokens that a larger target model verifies in a batched forward pass.
Also called: speculative decoder, predicted outputs
Why it matters: It cuts inference latency substantially without changing the final model's output, making it one of the most popular tricks for serving large models cheaply.
For example, a tiny draft model proposes the next eight tokens of an answer, and the big model checks them all in a single forward pass — keeping the ones that match its own predictions.
Heard on the show
“The fix everybody already uses is speculative decoding.”Episode 179 — How DeepSeek Made One User Faster Without Slowing Down the Crowd