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

# Custom Headers

> Unique headers used in API v1 to control authentication, data selection, and request routing.

API v1 uses custom HTTP headers to provide metadata for encryption, decryption, and authentication for legacy proxy
requests.

# Authentication Header

<ParamField header="X-Qanapi-Authorization" type="string" required>
  Your unique API key used for authentication.
</ParamField>

# Content Control

<ParamField header="X-Qanapi-Mode" type="string" required>
  Specifies the action to perform on the payload.

  **Allowed values:** `encrypt`, `decrypt`
</ParamField>

<ParamField header="X-Qanapi-Fields" type="string" required>
  A comma-separated list of field names in the JSON payload to be processed.
</ParamField>

<ParamField header="Content-Type" type="string" required>
  Must be set to `application/json` for all requests containing a JSON payload.
</ParamField>

# Advanced Routing

<ParamField header="X-Qanapi-Destination" type="string">
  A URL to forward the encrypted data to. If provided, the processed payload will be sent to this destination instead
  of being returned to the client.
</ParamField>

<Warning>
  When using `X-Qanapi-Destination`, all non-Qanapi headers will be forwarded to the destination URL along with the
  processed payload.
</Warning>

<Card title="Try it out" icon="vial" href="/v1/overview">
  Learn more about legacy v1 proxy requests in the overview.
</Card>