Are you not familiar with out of process COM servers? A lot of Office automation is out of process, even inside of Office itself. Admittedly I’m not sure about

Are you not familiar with out of process COM servers? A lot of Office automation is out of process, even inside of Office itself. Admittedly I’m not sure about the grammar checker specifically. As for the Spellcheck API, external providers are explicitly out of proc: https://learn.microsoft.com/en-us/windows/win32/intl/about-the-spell-checker-api https://learn.microsoft.com/en-us/windows/win32/intl/about-t... Anyway, my point still stands - building desktop apps using composition over RPC is neither new nor a bad idea, although HTTP might not be the best RPC mechanism (although… neither was COM…)