This pyramid chart shows the hierarchy of canon sources I use when writing Harry Potter fanfiction.
At the top of the pyramid are the HP novels: people, places, things, and events from the seven published HP novels take precedence over other sources.
Beneath that are other books: Fantastic Beasts, Quidditch Through the Ages, Beedle the Bard, Cursed Child.
Beneath that is Pottermore: everything published on Pottermore I consider semi-canon.
Beneath that is films: the eight HP films plus the ongoing Fantastic Beasts films.
At the bottom of the pyramid is everything else: interviews, tweets, etc. are extra-canon.