OpenAI said on Monday that it would soon wind down the availability of GPT-4.5, its largest-ever AI model, via its API. GPT-4.5 was released only in late February.

Developers will have access to GPT-4.5 via OpenAI’s API until July 14, after which they’ll have to transition to another model in OpenAI’s catalog, the company says. OpenAI is positioning GPT-4.1, which launched Monday, as the preferred replacement.

“[GPT-4.1] offers similar or improved performance than GPT-4.5 in key areas at a much lower cost,” an OpenAI spokesperson told TechCrunch via email. “[W]e will [be] deprecating GPT-4.5 to prioritize building future models.”

To be clear, GPT-4.5 isn’t leaving ChatGPT, where it’s available in research preview for paying customers. OpenAI is only phasing it out of the API.

GPT-4.5, code-named Orion, was trained using more computing power and data than any of OpenAI’s previous releases. It improves upon its predecessor, GPT-4o, in areas such as writing and persuasiveness, but despite its scale, GPT-4.5 falls short of “frontier-level” on a number of industry benchmarks.

GPT-4.5 is also very expensive to run, OpenAI admits — so expensive that the company warned in February that it was evaluating whether to serve GPT-4.5 via its API in the long term. The model’s pricing reflects this: GPT-4.5 costs $75 for every million input tokens (roughly 750,000 words) and $150 per million output tokens, making it one of OpenAI’s costliest offerings.