Auth0 Device Flow is an OAuth 2.0 authorization implementation designed for browserless or input-constrained devices that need to access APIs. The solution addresses authentication challenges for devices without traditional input mechanisms like full keyboards or browsers, such as smart TVs, IoT devices, and sensor hubs. The authentication process uses a two-step flow where users authorize devices through a secondary device with a browser, such as a smartphone or computer. The primary device generates a URL and/or code, which the user then enters on the secondary device to complete authentication without directly inputting credentials into the constrained device. The solution is applicable to smart TV applications, media streaming services, and consumer IoT devices. For IoT devices without displays, the flow can work when connected via network to a smart controller or hub that has a display to present the authorization code and URL. Auth0 provides a developer playground with a simulated smart TV environment for testing and learning the Device Flow implementation. The solution maintains security while improving user experience on devices where traditional credential entry would be difficult or frustrating.