Why does my API key only access GPT-3.5 despite my GPT-4 Plus subscription?

Below is some clarification regarding your situation:

API Keys and Model Access

• API Keys & Prefix:
  All OpenAI API keys start with “sk-” by design. This prefix doesn’t indicate whether the key provides access to GPT-3.5 or GPT-4. It's simply the standard format for API secret keys.

• ChatGPT Plus Subscription vs. API Access:
  A GPT-4 (ChatGPT Plus) subscription applies to the ChatGPT product interface. API access is managed separately. Even if you’re a GPT-4 Plus subscriber, your API usage defaults to GPT-3.5 unless you explicitly use a GPT-4 model endpoint—and only if your API account has been granted access to that model.

• Specifying the Model:
  When making API calls, you need to specify the correct model (e.g., "gpt-4-0613", "gpt-4-turbo", or similar) in your request. If no model is specified or if you’re restricted to GPT-3.5 endpoints, then your calls will use GPT-3.5 by default.

Recommendations

1. Check Model Access:
   Verify that your API account has been enabled for GPT-4 (or GPT-4 Turbo/GPT-4o, depending on your intended usage). Being a GPT-4 Plus subscriber in ChatGPT doesn’t automatically grant API access to GPT-4.

2. Review Your API Requests:
   Confirm that your API requests are targeting the correct model endpoint by explicitly setting the model parameter. For example:

   PYTHONCopied
   import openai
   
   response = openai.ChatCompletion.create(
       model="gpt-4-0613",  # or the specific GPT-4 model you intend to use
       messages=[{"role": "user", "content": "Hello, how does GPT-4 work?"}]
   )

3. Billing and Rate Limiting:
   While you mentioned adding a $5 prepaid balance, ensure that your API usage is within your quota and that you aren’t inadvertently hitting rate limits specific to your account or the model endpoint.

If you continue to encounter issues, it might be helpful to contact OpenAI support to ensure that your API permissions are set up correctly for GPT-4.