Do white spots mean my German Shepherd puppy isn't purebred?

Thanks for visiting Petcoach. This breed often can have white or tannish colors throughout the coat. There are also some German Shephards who are purely white. Take a look at this link about the breed and it talks about this further down the page. https://dogtime.com/dog-breeds/german-shepherd-dog#/slide/1

Here is an excerpt from the website link "The coat comes in variety of colors and patterns including black; black and cream; black and red; black and silver; black and tan; blue; gray; liver; sable; and white. The American Kennel Club doesn't recognize white as a color for this breed, however, and won't let white German Shepherds compete in conformation shows, although they're allowed in other competitions."

Best wishes with your puppy! Take care.