How do payment gateways work in Marketplace?

Marketplaces have their own exclusive challenge of paying to 1000’s of their sellers. It is very hard for a marketplace to form a whole system for paying their sellers as well as handling stuffs like safeguarding the system, paying the sellers after cutting their share, join in numerous payment processors and also handling payments to diverse bank accounts of sellers. I would like to know how payment gateways work in marketplace. Can someone explain me how payment gateways work in marketplace?