What is difference between die cut and kiss cut stickers?

Die Cut Stickers:

The key feature of a Die Cut Sticker is how the backing of the sticker aligns exactly with the shape and size of the sticker itself. Die cut stickers are cut straight through the vinyl and paper backing to fit the exact shape of your design. This makes for a great looking sticker even before it's applied.

Kiss cut stickers:

Kiss cut stickers are only cut through the vinyl -- the paper backing stays intact. You can print on the vinyl around a kiss cut sticker to add extra style to your design. Kiss cut stickers are ideal for delicate designs as the backing helps protect your sticker while it's being transported.

Both the Die Cut and Kiss Cut Stickers are digitally printed on white polypropylene.

Die cut stickers vs kiss cut stickers:

Kiss cut stickers is very similar to a die cut stickers[1]. However, the main difference is the sticker backing isn’t cut to the shape of the sticker. A Die Cut Sticker is a sticker that is cut to the shape of the sticker.

Die Cut Stickers are stacked and shrink-wrapped. Some advantages to die-cutting would be if sticker needs sharp corners. In general, it is a good idea to round the corners of a die cut or kiss cut to avoid creating a rip point.