Empty OPENAI_BASE_URL prevents fallback to default API endpoint

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
68/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Quiet
Tech stack
python
Domain
api

Research direction

Start in src/openai/_client.py at the base_url initialization logic linked in the issue, then reproduce the behavior with OPENAI_BASE_URL set to an empty string and client.models.list(). Done means the client uses the documented default endpoint instead of producing a connection error in this environment.

Written by the indexing model from the issue text.

Description

bug
Confirm this is an issue with the Python library and not an underlying OpenAI API
  • This is an issue with the Python library
Describe the bug

I noticed a small issue in the base_url initialization logic: (https://github.com/openai/openai-python/blob/656e3cab4a18262a49b961d41293367e45ee71b9/src/openai/_client.py#L163-L166)

if base_url is None:
    base_url = os.environ.get("OPENAI_BASE_URL")
if base_url is None:
    base_url = f"https://api.openai.com/v1"

If the environment variable OPENAI_BASE_URL is defined but empty (e.g., OPENAI_BASE_URL=""), then os.environ.get("OPENAI_BASE_URL") returns an empty string. As a result:

  • base_url becomes ""
  • the second condition (if base_url is None) is never triggered
  • the intended fallback "https://api.openai.com/v1" is skipped

An empty string is not a valid base URL, so this can lead to confusing behavior.

To Reproduce
  1. export OPENAI_BASE_URL=""
  2. run the following:
from openai import OpenAI

client = OpenAI()
client.models.list()
  1. Trigger an "openai.APIConnectionError: Connection error" error
Code snippets
OS

macOS

Python version

Python 3.12.2

Library version

2.15.0

Dominant language
Python
Stars
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Forks
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Avg merge
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Merged PRs (30d)
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