Do LTIs slow down canvas?
My organization makes external pages to supplement online courses on canvas. We are thinking of making an LTI to inject these static sites into the courses and be able to pass back a grade for completion. That would be an average of 8 static sites per course, and we have 100+ courses. We're building more every semester.
Would canvas take a huge hit in performance if we went this route?
LTI tools run independently of Canvas (typically on infrastructure operated by you, or a vendor), so there's no performance impact to Canvas itself associated with having a lot of LTI tools installed.
From a user perspective, the experience of the performance of the page will mostly depend on how quickly your LTI tools return content. There are a couple of redirects that happen when a user launches an LTI tool in Canvas, but usually they happen quickly enough to not really be noticeable.
For comparison, we have many thousands of courses in our Canvas instance, and hundreds of LTI installs across courses and sub-accounts; I haven't noticed any decrease in performance as we've grown these numbers over the years.