TheTVDB

The stated aim to be the most complete and accurate source of information on TV series from many languages and countries.

It provides a repository of series, season and episode images that can be used in various types of home theater PC software to make the visual interface experience more appealing.

[1] The site has a full JSON API that allows other software and websites to use this information.

The API is currently being used by the myTV add-in for Windows Media Center, Jellyfin, Zappiti, Kodi (formerly XBMC); Plex; the meeTVshows and TVNight plugins for Meedio (a digital recorder acquired by Yahoo.com); the MP-TVSeries plugin for MediaPortal, Numote (iPhone/Android app and set-top device), and more.

As of 2020, the API now requires a license subscription from either application developers or end users.