One thing to call out if you’re unsure if it’s actually GPT-4, is to check your API usage requests which will tell you which model you’re using.
Also worth noting that chat GPT-4 API does not “remember” your responses like when using it in the browser. To have a conversation with it, you need to constantly update and provide the previous conversation to it for context.
You achieve this by saving the previous response and adding it to the messages array every time you make a new API request / chat message. You can find a JavaScript example request here.