Payment Processors for Groestlcoin GRS GRSPay GRSPay Server is a free and open source server for merchants wanting to accept Groestlcoin for their business. The payment server does not need to know your private keys, so your money is safe. CoinPayments Payment gateway providing buy now buttons, shopping carts, and more to accept Groestlcoin, and other cryptocurrencies/altcoins on your website/online store. CoinToPay The Modern Currency Payment Provider you can trust. Supporting Bitcoin, Ethereum, Groestlcoin, Litecoin, Decred, Monero, and many more.