Use this guide to understand the possibility of sending an API request to QR API without an API Key.
Technically, it is possible to send an API request, without the API key parameter or with an invalid API key. In both cases, a QR Code image with a 'preview' watermark will be returned.
QR Codes with preview watermarks are NOT scannable using most QR Code scanning applications.
If you still have questions related to this topic, feel free to reach out to our customer relations team at firstname.lastname@example.org.