Connection Doctor

Find out why your API key is not working.

Start with a no-token authentication check. We explain the difference between an invalid key, missing permissions, quota exhaustion and a browser CORS block.

Privacy boundaryBrowser → selected provider

Keys are not sent to FreeToken.link or stored by this page.

Direct key check

No arbitrary endpoints and no FreeToken proxy in this first version.

Browser direct

Provider

API key

Ready for a direct check
Select a provider and paste your own key.

What the result proves

Evidence is intentionally narrow and explicit.

200	Key authentication passed for the tested endpoint.
401 / 403	Invalid key, wrong key type or missing permission.
429	Provider recognized the request but quota was reached.
CORS	Browser blocked the request; test locally with a generated config.