I have noticed that some city and state government websites allow people to pay their utility bills online (water, gas, electric).
However, the majority that I have seen that offer online bill pay simply redirect the site visitor to a different URL. It seems as though the local government has an arrangement with a company that specializes in receiving online bill payments. This would eliminate the need for a programmer to actually code bill payment features into the government site itself (save for a link).
My question is this: how common is it for a city or state government site to actually have payments processed on their own server? Or do government sites exclusively link to a separate online merchant service that does it for them?