Starting today, YouTube is rolling out a new embeddable subscribe button that will allow users to subscribe to channels from outside of YouTube. Channel owners can embed the new subscribe button on their websites and else where using the code below. Above is an example of the new subscribe button embedded on Vice.com.
To put the subscribe button on your site, just embed the code below like you’d embed a YouTube video.
<div data-channel=”Your Channel Name Here”>
Check out this documentation if you want to customize the button or dive into the details.