What causes "Missing api_key, make sure you pass in your api key" in BerriAI/litellm?

export BYTEZ_API_KEY= (from your Bytez account) in the runtime environment.

BerriAI/litellm · critical · Exception

Missing api_key, make sure you pass in your api key

Error message

Missing api_key, make sure you pass in your api key

What it means

In the same validate_environment call, Bytez requires an api_key (used as 'Authorization: Key <api_key>'). If api_key is falsy, this Exception is raised client-side before the request is sent. Bytez keys are resolved through litellm's standard api_key flow, so this means neither the argument nor BYTEZ_API_KEY was available.

Source

Thrown at litellm/llms/bytez/chat/transformation.py:138

        messages: list[AllMessageValues],
        optional_params: dict,
        litellm_params: dict,
        api_key: str | None = None,
        api_base: str | None = None,
    ) -> dict:
        headers.update(
            {
                "content-type": "application/json",
                "Authorization": f"Key {api_key}",
                "user-agent": f"litellm/{version}",
            }
        )

        if not messages:
            raise Exception("kwarg `messages` must be an array of messages that follow the openai chat standard")

        if not api_key:
            raise Exception("Missing api_key, make sure you pass in your api key")

        return headers

    def get_complete_url(
        self,
        api_base: str | None,
        api_key: str | None,
        model: str,
        optional_params: dict,
        litellm_params: dict,
        stream: bool | None = None,
    ) -> str:
        encoded_model: Final = encode_url_path_segments(model, field_name="model")
        return f"{API_BASE}/{encoded_model}"

    def transform_request(
        self,
        model: str,

View on GitHub (pinned to 6c2dcb801b)

Solutions

export BYTEZ_API_KEY=<key> (from your Bytez account) in the runtime environment.
Or pass api_key directly to the completion call.
On litellm proxy, add api_key to the bytez provider's litellm_params entry.

Example fix

# before
litellm.completion(model="bytez/meta-llama/Llama-3-8b", messages=m)

# after
litellm.completion(model="bytez/meta-llama/Llama-3-8b", messages=m, api_key=os.environ["BYTEZ_API_KEY"])

Defensive patterns

Strategy: validation

Validate before calling

import os

if not (os.getenv("BYTEZ_API_KEY") or provided_api_key):
    raise RuntimeError("BYTEZ_API_KEY missing; configure it before serving traffic")

Try / catch

try:
    litellm.completion(model="bytez/...", messages=m)
except Exception as e:
    if "Missing api_key" in str(e):
        raise SystemExit("Config error: set BYTEZ_API_KEY") from e  # config failure, never retry
    raise

Prevention

Assert required provider keys at process startup.
Document every env var your deployment needs in one checklist.
Alert on auth-config errors separately from runtime API errors.

When it happens

Trigger: Calling litellm.completion(model="bytez/...", ...) with no api_key argument while BYTEZ_API_KEY is unset in the environment.

Common situations: Missing env var in new environments/CI; key stored under a different name; proxy deployments where the key isn't configured for the bytez provider.

Related errors

AI-assisted analysis of BerriAI/litellm@6c2dcb801b (2026-08-15). Data as JSON: /api/errors/68115b97477350dc. Report an issue: GitHub.