Troubleshooting OpenAI Base URLs
Switching models should be easy. You change the endpoint and keep the SDK.
In real projects, the first run often fails. You see errors like 401, 404, or 429.
Use this checklist before you blame the SDK.
Check the /v1 prefix Most gateways need the /v1 suffix in the URL. If you use only the domain, the SDK might call the wrong path. Copy the exact format from the provider docs.
Verify your API keys Mixing keys causes failures. Check these common mistakes: • Using an OpenAI key with a relay URL. • Using a relay key with an OpenAI URL. • Using a key from a disabled project. • Including a space at the start or end of the key. If you see a 401 error, print the first and last characters of your key to compare it with your dashboard. Do not log the full key.
Match model names exactly Do not guess model names. Gateway names change. A wrong name leads to 404 or model_not_found errors. Copy the model ID directly from the current model list.
Run a tiny request first Before debugging your whole app, run a small test. Use a simple "ping" message and low max_tokens. If this works, your URL, key, and model are fine. Your bug lives in your app logic, such as streaming or tool calling.
Understand error codes • 401 means a key or account issue. • 429 means a rate limit or balance issue. If you see 429, check your billing page. Avoid tight retry loops. They make the problem worse.
Check the status page If your code worked yesterday but fails today, do not rewrite your integration. Check the provider status page first. An upstream incident is often the cause.
Use a curl command Keep a simple curl command in your project docs.
When your app breaks, run the curl command first. If curl fails, the problem is the account, gateway, or network. If curl works, the problem is your app code.