BerriAI/litellm · error · ValueError

LINKUP_API_KEY is not set. Set `LINKUP_API_KEY` environment…

Error message

LINKUP_API_KEY is not set. Set `LINKUP_API_KEY` environment variable.

What it means

The Linkup search transformation authenticates with a Bearer token. resolve_server_api_key checks the caller-supplied api_key and the LINKUP_API_KEY environment variable; when neither yields a key, validate_environment raises ValueError before any search request is sent, because the Linkup API cannot be called anonymously.

Solutions

Set the env var: export LINKUP_API_KEY=lk-... in the process making the call
Or pass the key explicitly as api_key on the search call
Add LINKUP_API_KEY to your deployment secrets (.env, docker env, k8s secret)
Confirm with printenv LINKUP_API_KEY from the same runtime

Example fix

# before
results = litellm.search(query="latest ai news", provider="linkup")  # ValueError: LINKUP_API_KEY is not set

# after
os.environ["LINKUP_API_KEY"] = "lk-..."
results = litellm.search(query="latest ai news", provider="linkup")

Defensive patterns

Strategy: validation

Validate before calling

import os

if not os.getenv("LINKUP_API_KEY"):
    raise SystemExit("Set LINKUP_API_KEY before using Linkup search")
# then: litellm.search(query=..., provider="linkup") will not raise on auth setup

Try / catch

try:
    results = litellm.search(query=q, provider="linkup")
except ValueError as e:
    if "LINKUP_API_KEY is not set" in str(e):
        raise ConfigError("Missing LINKUP_API_KEY environment variable") from e
    raise

Prevention

Fail fast at startup when search providers are enabled but their keys are absent
Keep provider API keys in a single validated secrets map loaded at boot
Add LINKUP_API_KEY to deployment secret manifests and CI checks

When it happens

Trigger: Any Linkup-backed web search (e.g. litellm.search / search provider 'linkup' or a model routed to linkup search) invoked without an api_key parameter and without LINKUP_API_KEY present in the environment.

Common situations: Env var missing in the deployed environment or CI; key stored under a different name (LINKUP_KEY, LINKUP_API_TOKEN); local shell has it but the server process does not.

Understand the failure class

Background: "API key is required" / "API key not found" / "No API key was set": the missing-api-key error family across 16 libraries — this error's family across 16 libraries.

Related errors

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/14d5d8466ddb7703. Report an issue: GitHub.

Appendix: source

Thrown at litellm/llms/linkup/search/transformation.py:70

    def validate_environment(
        self,
        headers: dict,
        api_key: str | None = None,
        api_base: str | None = None,
        **kwargs,
    ) -> dict:
        """
        Validate environment and return headers.
        """
        api_key = self.resolve_server_api_key(
            caller_api_key=api_key,
            caller_api_base=api_base,
            key_env_vars=("LINKUP_API_KEY",),
            base_env_var="LINKUP_API_BASE",
            default_api_base=self.LINKUP_API_BASE,
        )
        if not api_key:
            raise ValueError("LINKUP_API_KEY is not set. Set `LINKUP_API_KEY` environment variable.")
        headers["Authorization"] = f"Bearer {api_key}"
        headers["Content-Type"] = "application/json"
        return headers

    def get_complete_url(
        self,
        api_base: str | None,
        optional_params: dict,
        data: dict | list[dict] | None = None,
        **kwargs,
    ) -> str:
        """
        Get complete URL for Search endpoint.
        """
        api_base = api_base or get_secret_str("LINKUP_API_BASE") or self.LINKUP_API_BASE

        # Append "/search" to the api base if it's not already there
        if not api_base.endswith("/search"):

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