You might want to consider using https://thetvdb.com/ for your data source. It still has problems, but overall it seems to be more accurate than IMDb.
Trakt has written a blog post[1] switching all of the shows on their platform over to be backed by TMDB (once the data is on par with TVDB), so it might even be the best data source for series in the future.
So you could choose to use TVDB (paid) or TMDB (free). The data seems to be on par, except for specials[2]. But if you use Trakt's API (free) you'll automatically get the best current source of these two.