Any mature SaaS CMS solution out there

Looking for mature SaaS CMS solution out there that has a .NET api or RESTful api.

The minimum requirement are:

• A nice interface for content editing
• The ability to sync content across servers (dev/st开发者_如何学Pythonaging/production)
• Versioning (rollback)
• Workflow
• Role based permission
• (all other cms goodies)

DotNetNuke has almost all of the features you required. It is an opensource CMS project that has large community to interact. If it doesn't include the solution you are looking for then you may always find the one from the community that develop custom modules.

Suggest you to check that out.