Wide as the opening and two steps across. Look for a commercial mat.

Thank you, any idea on where to find that?

I 'd prob do something this size, with the warmer tones and the black

if you can't find one the right size, do an outdoor rug, and layer the floor mat on top of it:

But there are a million color/pattern combos you could use. you could even leave a tray if you want people to remove their shoes.

if you like the pebble look, they make mats w/that too.

Or, Diy your own

you can even cut into the concrete and install your own pebbles

Thank you, I need something that can get wet.

I would recommend measuring the space in front of the door, you are probably going to need something custom made for it. But measurements would be the first stage so you know how big you want the rug.

You may be able to try a carpet company (in your local area) or possibly Wayfair, possibly even Etsy might be a place to look.

Check out Chilewich they have great totally hoseable mats in lots of custon sizes and colors

Staples or any office supply store has tons of mats.