Best Cheminformatics API for drawing SMARTS reactions?
OpenEye is probably the most powerful and fast depiction SDK, but it costs money. Also OpenEye is a low-level, cumbersome, complicated library - so I'd consider it only if you have very sophisticated needs. It's written in C++, but it has Python/Java wrappers.
CDK (Java) has an OS-agnostic depiction API, works great for simple needs, haven't tried anything super complicated.
I tried Indigo several years ago and it worked fine, maybe you misconfigured it? Though it did require an additional OS-level dependency for fonts (Cargo?) on Linux. Don't remember if there were problems with other OS's.