openai_api_base

Base URL path for API requests, leave blank if not using a proxy or service emulator.

Resolution order (first match wins):

1. Explicit base_url (or openai_api_base) kwarg.
2. Env var OPENAI_API_BASE (read by LangChain at init).
3. Env var OPENAI_BASE_URL (read by the underlying openai SDK client).