In that case, for email please check out Aurinko API https://docs.aurinko.io/unified-mailbox-api/email-api

Which payroll platforms are important to you?

We are also building a virtualization layer, so you could configure a virtualized unified API for your specific needs provided that we have the required connectors. https://www.aurinko.io/blog/virtualized-unified-api/

Email me at alexey at aurinko.io if you have quesitons.