Did anyone here ever created a whitelabel for their own saas?

I worked with a couple of Fintechs who did this with their payment solutions. They were mostly API driven and basically back ended specific capabilities for some larger banks while also running their own smaller service under their own license.

Whitelabel or API integration? very different things. All SaaS I worked for had a public API (of varying qualities and scope), only very few added Whitelabeling UI/Front.