What I do
End-to-end: I can build the software and run it for you, or just do one half of that. Hosting lives on infrastructure I maintain.
Web apps and tools built to fit, mostly .NET on the back end with a modern front end.
Your app deployed on managed infrastructure, each client isolated on its own subdomain.
Updates, monitoring and fixes so what you launched keeps running smoothly.
Architecture, infrastructure and "how should we build this" conversations.