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Authentication should be checked at the sending process; changing GPU settings does not repair an invalid or missing credential.
When OpenRouter returns 401, start with authentication: did the process receive the correct key, send the Bearer header and use access that is still valid? GPU memory, context length and token-generation speed usually do not explain this rejection. Verify the credential boundary before changing the workload.
Inspect the sending side safely
OpenRouter uses Authorization: Bearer … for API-key authentication. Confirm that the actual external request contains the expected header structure. A key saved in an application’s interface does not prove its server adapter reads that setting or forwards it correctly.
Do not print the full header to prove it exists. Record a non-secret indication that configuration was supplied, plus the destination and response status. Check for surrounding whitespace or an incorrect variable name without copying the working secret into a shared issue or screenshot.
Match the credential to the process
| Runtime | What to verify |
|---|---|
| Local shell | The intended shell launches the intended program |
| Container | The setting is passed into the container |
| System service | Its configuration was updated and the process restarted |
| Development and production | Keys have not been assigned to the wrong environment |
A terminal can contain a new value while a long-running service continues using the old one. Identify the process, deployment and environment that made the failing call. Avoid debugging another copy of the application on a different port and assuming its settings apply to production.
Confirm that access remains valid
The documented 401 conditions include invalid or disabled credentials. Check the key’s state in the authorized account and review recent rotation or revocation. A revoked secret should stop working; that is expected behavior rather than a model failure.
Use one minimal, permitted request with a small output limit to isolate authentication. Keep the API address, operation and checked model identifier unchanged. Compare safe error fields and the time of the attempt, not private prompt contents. An unrelated account’s successful call does not establish that this application’s credential is valid.
Replace and verify systematically
Inventory every dependent service before replacing a credential. Update the intended secret source, restart processes where required and test each dependency with a small allowed operation. Separately confirm that the old value no longer works. Avoid leaving an unexplained mixture of old and new configuration across workers.
Document ownership and the next review date, then resume application testing. For a hardware proposal, keep authentication readiness separate from local serving capability. Neither an API credential nor a successful login proves an approved distribution relationship or demand for new capacity.
Official references: openrouter.ai — authentication, openrouter.ai — errors and debugging.
Related guides: Setting up an OpenRouter API key for an application, OpenRouter base URL: configuring a compatible client.