Can GPT's be accesed with a API or smth?

[PaulBellow]

Custom GPTs are only available via ChatGPT Plus while Assistants have an API.

API assistant VS GPTs: what's the main difference?

Are GPTs just assistants on the backend with all the tedium of building the thread and the polling routine pre-built and exposed through a canned interface? It very much appears that way. Essentially, yes!