Why i got different results when using Chat GPT API vs using Chat GPT UI

I have developed an SPFx web part using react js >> the web part integrate with chat GPT >> now i generate an API (seems it is free as i were not asked to pay ot provide any payment method) . but i noted that i will get different result when using chat GPT UI VS Chat GPT API.

here is what i get when using the API for key value reference why it is secure VS what i get when using the UI,where i will get more text when using the UI compared to the API:-

any advice about this differences ?

so what is the reason i will get different result?