BerriAI/litellm · error · ValueError

api_base is required for Azure AI FLUX 2 image generation

Error message

api_base is required for Azure AI FLUX 2 image generation

What it means

Error "api_base is required for Azure AI FLUX 2 image generation" thrown in BerriAI/litellm.

Source

Thrown at litellm/llms/azure_ai/image_generation/flux_transformation.py:39

        api_version: str | None,
    ) -> str:
        """
        Constructs the complete URL for Azure AI FLUX 2 image generation.

        FLUX 2 models on Azure AI use a different URL pattern than standard Azure OpenAI:
        - Standard: /openai/deployments/{model}/images/generations
        - FLUX 2: /providers/blackforestlabs/v1/flux-2-pro

        Args:
            api_base: Base URL (e.g., https://litellm-ci-cd-prod.services.ai.azure.com)
            model: Model name (e.g., flux.2-pro)
            api_version: API version (e.g., preview)

        Returns:
            Complete URL for the FLUX 2 image generation endpoint
        """
        if api_base is None:
            raise ValueError("api_base is required for Azure AI FLUX 2 image generation")

        api_base = api_base.rstrip("/")
        api_version = api_version or "preview"

        # If the api_base already contains /providers/, it's already a complete path
        if "/providers/" in api_base:
            if "?" in api_base:
                return api_base
            return f"{api_base}?api-version={api_version}"

        # Construct the FLUX 2 provider path
        # Model name flux.2-pro maps to endpoint flux-2-pro
        return f"{api_base}/providers/blackforestlabs/v1/flux-2-pro?api-version={api_version}"

    @staticmethod
    def is_flux2_model(model: str) -> bool:
        """
        Check if the model is an Azure AI FLUX 2 model.

View on GitHub (pinned to 6c2dcb801b)

Solutions

1. Pass api_base for the Azure AI FLUX 2 image generation call.

When it happens

Trigger: Thrown at litellm/llms/azure_ai/image_generation/flux_transformation.py:39 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@6c2dcb801b (2026-08-15). Data as JSON: /api/errors/74b1804af89bdf95. Report an issue: GitHub.