OpenAI API · sdk · fg-0134

After upgrading openai-python to 3.x, import httpx fails, respx mocks stop working, or TLS verification breaks

ModuleNotFoundError: No module named 'httpx'

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

openai-python 3.0.0 switched to HTTPX2 and stopped installing httpx and certifi. HTTPX2 trusts the operating system certificate store, and only HTTPX2 clients satisfy the type hints.

Fix

Migrate custom clients and mocks to httpx2 equivalents, install system CA certificates or set SSL_CERT_FILE, and add httpx yourself only as a temporary bridge.

Apply

import httpx2
from openai import OpenAI, DefaultHttpx2Client
client = OpenAI(http_client=DefaultHttpx2Client(timeout=httpx2.Timeout(30.0)))
# TLS: export SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt

Affects: openai-python 3.0.0 (2026-08-12) and later

Sources

• https://github.com/openai/openai-python/blob/main/httpx2.md
• https://github.com/openai/openai-python/releases/tag/v3.0.0

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