We have just made publicly available the Payment Provider Framework (PPF), which is an alternative way to develop payment connectors through VTEX IO. This feature is in the beta stage.
Before PPF, the only way partners could develop connectors for payment integrations was by implementing our Payment Provider Protocol (PPP) in their infrastructure. Partners would have to implement their solution with all the required endpoints and deal with hosting the connector.
With PPF, since the development is based on an IO app boilerplate, a lot of the work is already done to accelerate the implementation of your integration. Also, developers do not need to worry about hosting the connector since it is hosted on the IO infrastructure.