GIF to WebP converter
You can also use: http://ezgif.com/gif-to-webp?url=http://link/to/image.gif
Online GIF to WebP converter
A simple online tool that lets you upload and convert GIF images (including animated) to WebP format.
WebP is a more modern and complex image format, with various compression methods and 24-bit color with transparency, also supporting animations. It has the benefit of smaller file size while providing better image quality than GIF, but it's not yet fully supported natively by all major web browsers and image editors, so keep that in mind if you are planning to use WebP files. You can read more about WebP support at wikipedia.org
At this moment ezgif.com has only partial support for WebP editing, but you can convert any GIF to WebP after editing if you wish.