The base of the QR code is its actual support. It could be physical, namely printed on a label, or digital, in a digital wallet or web page.

The payload embedded on the QR code can be directed at different audiences.

• A public audience defines a lambda user that can read the content without previous steps (for example, registration) or knowledge.
• A private user has an expected purpose of the QR code and possesses a dedicated application to read a custom payload.

The payload carries information through two non-mutually exclusive means. The most common way is via a URL, linking web resources that can be accessed with any QR code reader. Alternatively, the payload could be a custom package, as plain text or with a structured language.

The choice of the reader depends on the target audience (public/private) and the type of payload (custom package). The three options include:

• The default smartphone applications allowing any users with a phone to access the linked resource;
• A custom-developed smartphone application which makes custom data accessible to targeted users; and
• A web-based application, with a similar principle as the custom one but which relies on the use of an external scanner, such as a webcam, camera or dedicated hardware.