Whether you are traveling to foreign countries or searching for a local restaurant the HappyCow App and website are the single best resource to use.
The app does cost $3.99 but the cost is justified. We have used it in Europe and found great restaurants not listed in guidebooks or blogs.
One can search by Vegan, Vegetarian, or Veg Options (meaning has both veg/vegan and meat/dairy). There are clear ratings and descriptions with business hours that seem to be up to date.
There are free apps, as well, but I would go straight to HappyCow. It is well worth it!