What is speculative decoding, and when does it actually help?
Free tokens from idle FLOPs, losslessly, which surprises most candidates. The mechanism, the acceptance-rate math, and the high-batch regime where speculation quietly stops paying.
Updated Sep 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
Free tokens from idle FLOPs, losslessly, which surprises most candidates. The mechanism, the acceptance-rate math, and the high-batch regime where speculation quietly stops paying.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
