Option #2 – Detect the type of device and serve the appropriate pages
This is done by doing a sniff of the device or user-agent. You keep one URL, but maintain multiple pieces of code. The benefit is that you can customize the user experience to the type of device, and it can be faster loading than a responsive website.
The Gotcha: This isn’t ideal because it means that if you’re updating content, if you don’t have a CMS, then you have to keep your content updated on all device-specific pages.
Who should do this?
This is good for companies who have regular IT staff or vendors to manage the different sets of website code .