LiteLLM

pip install litellm

import os
from litellm import completion

response = completion(
    model="openai/openai/gpt-5-nano",
    api_key=os.environ["PHASEO_API_KEY"],
    api_base="https://api.phaseo.app/v1",
    messages=[{"role": "user", "content": "Reply with only: ok"}],
)

print(response.choices[0].message.content)

model_list:
  - model_name: phaseo-gpt-5-nano
    litellm_params:
      model: openai/openai/gpt-5-nano
      api_key: os.environ/PHASEO_API_KEY
      api_base: https://api.phaseo.app/v1