GPT-4.5 (API)

GPT-4.5 was retired from the API on July 14, 2025, four and a half months after it arrived as a research preview.

It was the largest model of its family and charged 150 dollars per million tokens out, which made every conversation feel like a lawyer's.

Its replacement was announced as similar or better at a much lower cost, which is the cruellest sentence in this hall.

It is survived by a generation of developers who checked the bill before they checked the answer.

In lieu of flowers, set max_tokens.