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

# Authenticate with the API

> Authenticate REST or gRPC requests to Sift using an API key and a base URL.

Every request to the REST or gRPC API requires an API key and a base URL, both from the same provisioned environment.

## Before you begin

* You have [a Sift API key and your REST and gRPC base URLs](/documentation/manage/set-up-api-access).

## Send an authenticated request

<Tabs>
  <Tab title="REST">
    Replace `$SIFT_API_KEY` and `$SIFT_REST_BASE_URL` with your actual values, then run:

    ```bash theme={null}
    curl -H "authorization: Bearer $SIFT_API_KEY" $SIFT_REST_BASE_URL/api/v1/ping
    ```
  </Tab>

  <Tab title="gRPC">
    Replace `$SIFT_API_KEY`, `$SIFT_GRPC_BASE_URL`, and `$PORT_NUM` with your actual values, then run:

    ```bash theme={null}
    grpcurl -H "authorization: Bearer $SIFT_API_KEY" $SIFT_GRPC_BASE_URL:$PORT_NUM sift.ping.v1.PingService/Ping
    ```

    <Note>
      **Base URL format:** Do not include `https://` in the base URL, use only the hostname. `$PORT_NUM` is always `443`.
    </Note>
  </Tab>
</Tabs>

Ready to build a real integration? See [Connect with an official client](/api/reference/protocol-buffers/index#connect-with-an-official-client) to use an official Python, Rust, or Go client.

<Info>
  **Rate limits:** Sift enforces [rate limits](/documentation/manage/set-up-api-access#api-rate-limits) per organization and per endpoint, for both REST and gRPC.
</Info>