How to use GPTs with api in my app

Now I use GPT-3 to produce my specified structured data。
But I need to put a large same inner-enterprise data in the Prompts every time,it costs tokens。
So I try to build a GPTs with the inner-enterprise data
I also have a question:How can I use my GPTs with api in my app

There is no direct api available for accessing a Custom GPT. You can create similar functionality using Assistants api and then use that via api.

Here is an example project if you wish to follow and setup with the help of a boilerplate to create a GPT using Assistant api and use it by embedding on a website or any other place