I have used Grab Taxi in Pattaya several times
It's not UBER.
It does have it's own APP.
Download it and you will get reasonable rates for GrabTaxi services.
The taxis I have been driven in are all regular taxis which have also signed up to get Grab Taxi customers.
No need to prepay.. but that option is new.
Various promotions for discounted fares occasionally sent to you by email.
Good drivers and reliable service from driver and Grab Taxi customer service online.
Tj