> ## Documentation Index
> Fetch the complete documentation index at: https://velocity-api-docs.medshift.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

Every request to the API must be authenticated using an API key set in the `X-API-Key` header.

```bash theme={null}
curl "https://{tenant}.api.velocity.medshift.com/integrations/zapier/v1/customers/" -H "X-API-Key: $YOUR_API_KEY"
```

You can find your API key in Velocity under **Velocity Settings → Integrations → Zapier**. It will always begin with `secret-token:`.

<Info>
  If you don't have access to the Zapier integration settings, please contact
  our support team.
</Info>

<Warning>
  **Keep your API key secret.** If you think it's been unintentionally shared,
  you can rotate it at any time from the Velocity settings.
</Warning>