OpenAI is switching off GPT-4o in its API on 14 January 2027, so the chatbot someone built you in 2025 needs a check-up
By Brett Gavaghan, Founder of Adaptd ·
OpenAI will remove GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini from its API on 14 January 2027. Custom chatbots and automations built on them need moving to a newer model before then.
The short version
- OpenAI will remove GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini from its API on 14 January 2027.
- It affects custom tools and automations that call these models through the API, including fine-tuned versions, not the ChatGPT app.
- Ask whoever built your AI tools which models they use, and test a move to gpt-6-luna before Christmas.
Somewhere in your business there may be a website chatbot, a quote generator or a Zap that someone set up in 2025 and nobody has touched since. If it runs on GPT-4o, it now has an expiry date.
What is OpenAI retiring?
OpenAI is retiring four GPT-4 series models from its API on 14 January 2027: GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini. OpenAI notified developers on 14 October 2026 and recommends gpt-6-luna as the replacement for all four.
Fine-tuned versions of these models, the ones trained on your own examples, follow the same shutdown date. Once a model is removed from the API, anything still calling it stops working.
Who does it affect?
The retirement affects businesses with custom software, chatbots or automations that call these models through OpenAI's API. People who use the ChatGPT app itself aren't the audience for this notice.
Common examples are a chat assistant on your website, a tool that drafts quotes or emails, or an AI step in Zapier or Make that names GPT-4o. If an agency or freelancer built it, the deprecation email may have gone to them rather than you. It's a bit like a car recall notice going to the previous owner.
What should your business do about it?
Businesses should find out which OpenAI models their custom tools use and plan the move to a newer model well before 14 January 2027.
My advice: send one short email to whoever built your AI tools and ask which models they call. Then test the switch on a copy first, because a new model can change the tone of replies, the length of answers or the layout of a quote. Leave it until January and you'll be testing over the summer holidays. Sort it before Christmas, while the person who built it still remembers how.
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