Isn't premium account enough to access API

I have a premium plan. Today for the first time I was trying to play around with API. I was testing with Postman but encountered following message.

“error”: {
“message”: “You exceeded your current quota, please check your plan and billing details.”,
“type”: “insufficient_quota”,
“param”: null,
“code”: “insufficient_quota”

Do I need to add extra billing information to be able to use API?

check your limit usage tiers

The “premium plan” you likely talk about is a subscription to ChatGPT Plus for $20 per month, the web chatbot.

API is a paid service billed by the amount of AI model data used at the price of that model.

If you do not have an existing payment method, you need to review how the service works and determine if it is actually going to be useful for you to program with. Then you must purchase pre-paid credits after entering a payment method into its separate billing system.

Thanks a lot, in the mean time I figured it out. Thank you for answering.