This API is a simple Flask-based API that takes a 'GET' request with a URL as a query parameter, converts it to a QR code image and returns it as the API response. The response is also set to be downloadable using the Content-Disposition header set to attachment and the filename attribute set to qrcode.png. The API uses the qrcode library to convert the URL to a QR code image. The API can be accessed by making a GET request to the endpoint '/qr-code' and passing the 'url' as a query parameter. This is a useful API for developers who need to generate QR codes for their projects and want to access the functionality via an API.