OpenAI
gpt-5.1 model retirement
Stops workingSubscribe to OpenAIShare
On April 1, 2027, model gpt-5.1 will be retired. This change affects calls using model gpt-5.1, as well as gpt-5.1-2025-11-13. After that date, these calls will fail.
The error you get from April 1, 2027
What OpenAI answers a call to gpt-5.1 once the model is gone, as recorded from real responses:
{"error":{"message":"The model `gpt-5.1` has been deprecated, learn more here: https://platform.openai.com/docs/deprecations","type":"invalid_request_error","param":null,"code":"model_not_found"}}What to use instead of gpt-5.1
Move to gpt-6-sol, which is the replacement recommended by OpenAI.
In OpenAI's words
Shutdown date: Apr 1, 2027; Model / system: gpt-5.1 | gpt-5.1-2025-11-13; Recommended replacement: gpt-6-sol
Facts
- API
- OpenAI
api.openai.com - Model
gpt-5.1- Released
- November 13, 2025 (models.dev)
- Kind
- Model retirement
- Takes effect
- April 1, 2027
- Calls after that day
- Fail
- Source
- Deprecations page
- Last updated
- Verified
- , against OpenAI's own pages
Questions
When does gpt-5.1 shut down?
Calls to the model gpt-5.1 on OpenAI stop working on April 1, 2027.
What happens to calls after April 1, 2027?
They fail from that day.
What error does gpt-5.1 return once it is shut down?
OpenAI answers HTTP 404: "The model `gpt-5.1` has been deprecated, learn more here: https://platform.openai.com/docs/deprecations". Send another model to fix it.
When was gpt-5.1 released?
gpt-5.1 was released on November 13, 2025, according to models.dev.
How do I find the calls this hits in my code?
Okapi reads your repository, finds the calls this change hits and opens a pull request with the fix. It never commits to your branches: every change comes as a pull request you review.
gpt-5.1 on other APIs 1
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Azure AI Foundry
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Is your code calling this?
Okapi finds the calls this change hits in your repo and opens the pull request with the fix before April 1, 2027.