Obviously, it doesn't have to be live. You can deploy to test.example.com and try it out there, but I think that's too late.
Easily detectable poor accessibility should be as much of a closed gate as having the layout go all wonky and the words all in the wrong place.
Ideally, it should be runnable on your local copy as you are writing it, just the same as viewing the page in a browser.
This code from IBM uses their own accessibility checklist, I'll be interested to see how it compares to axe-core.
The tools provide checking for WCAG 2.0 AA, WCAG 2.1 AA and the IBM checklist. The IBM checklist is basically WCAG 2.1 AA, but has some more strict requirements for defining landmarks for screen reader navigation.