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

# Authentication

> How to authenticate with the XFlow external API.

## How authentication works

External endpoints are protected by an API key that must be sent in the `Authorization` header using the `Basic` scheme. The value after `Basic` must be a Base64-encoded credential string.

The credential string is: `<client_id>:<api_key>`.

Where:

* `client_id` is your assigned client name or identifier.
* `api_key` is your secret key.

## Request format

1. Build the credential string: `<client_id>:<api_key>`.
2. Base64-encode the credential string.
3. Send it in the `Authorization` header using `Basic`.

### Example

```bash theme={null}
curl -H "Authorization: Basic <base64(client_id:api_key)>" \
  https://api.pulsy.app/v1/external/swaps
```

## Getting an API key

To request an API key for external access, contact [sales@pulsy.app](mailto:sales@pulsy.app).