ChatGPT API (gpt-3.5-turbo) Call Returning 400 Bad Request Error

It sounds like the issue might be due to the change in the expected request body structure for chat completions. With GPT-3 you likely used a "prompt" field, but with ChatGPT (gpt-3.5-turbo) you need to send a "messages" array. Make sure your JSON payload looks similar to the following:

BASHCopied
curl https://api.openai.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -d '{
    "model": "gpt-3.5-turbo",
    "messages": [
       {"role": "system", "content": "You are an avid story teller. You specialize in science fiction stories."},
       {"role": "user", "content": "Traveling Mars"}
    ],
    "temperature": 0.7
  }'

Note the following:

• Use the “messages” field: The ChatGPT API expects an array under the key “messages” instead of a single “prompt” string.
• Structure role messages correctly: The array should contain one or more objects with “role” and “content” fields. Common roles include "system", "user", and "assistant".

Double-check that your implementation sends the correct JSON structure. Adjusting your code to follow this format should resolve the 400 Bad Request error.