Does anyone knows if I can use the unlimited o1 mode with cursor (Im paying the o1 pro mode in Open AI $200) via API?
No. The OpenAI API is wholly separate from the ChatGPT product. They behave differently, and they do not make ChatGPT available via API. Your best bet is to copy and paste into ChatGPT, or use the ChatGPT native app with app usage to share your IDE view (current screen, basically as a screenshot) to see what you’re doing.
This all said, for $200 you can get a ton of usage of GPT-4o via API.
You can enable usage billing, which would enable you to use o1 within Cursor, and get charged based on what you use.
As @coreyward has said, you would have a lot of usage available to you for $200, but not unlimited!