Inference
Running a trained model to get an answer — everything that happens after training is done.
Inference is the production phase: the weights are frozen and the model simply maps input to output. It is where nearly all ongoing cost lives, because training happens once but inference happens on every request. Latency, price per token, and throughput are all inference concerns.
In practice: Every ChatGPT message you send is an inference call; the training run finished months earlier.