Hi team, I’m having the error:
You exceeded your current quota, please check your plan and billing details. For more information on this error, read the docs: https://platform.openai.com/docs/guides/error-codes/api-errors.
Even though I haven’t used the api this month.
I removed my API keys and created a new one and now I can’t use any API for free.
Is there a change where now we can just use OpenAI API by paying subscribtion?
The API is not billed on a subscription basis (and not connected to ChatGPT).
There also has never been any “API for free”.
What you may have had is a free trial credit, Which expired after three months or was exhausted.
Within your account at platform.openai.com, in the selection sidebar you can choose usage, and see the status of any grants.
In billing, the overview will show the balance you have in paid credits, and the option to add payment method and purchase some. (which expire within a year)
Thanks @_j for the helpful description 
I will check what you explain.