I’m trying to replicate the behavior of the ChatGPT web interface via the API, specifically regarding web search.
In the web UI, the “Instant” model (which seems to be gpt-5-chat-latest, the version without reasoning) can use the web search tool perfectly.
However, when I try to use either gpt-5-chat-latest through the API, the web search functionality is not available.
This brings me to my main question: How can we use a GPT-5 model without reasoning for web search via the API, to match the functionality already available in the ChatGPT interface?
Is there a specific configuration I’m missing, or is this feature currently unavailable through the API? Any guidance would be greatly appreciated.
At the moment, web search isn’t supported with GPT-5’s “minimal” reasoning mode. You can either implement a web search tool as a function to work around this, or switch to a higher level of reasoning when using web search.
We are looking at two versions of the same base model.
The chat variant is indeed the version used for ChatGPT but via API it doesn’t offer any of the tools that the actual GPT 5 does.
Using the chat variant via API is actually discouraged by OpenAI.
GPT-5 Chat points to the GPT-5 snapshot currently used in ChatGPT. We recommend GPT-5 for most API usage, but feel free to use this GPT-5 Chat model to test our latest improvements for chat use cases.