I created the database above a while ago using an xml file from the OpenExoplanet git repository github.com/OpenExoplanetCatalogue/open_exoplanet_catalogue/

As well as Tomas' link I think there are another a couple of possibilities with published API info.
So I've been taking part in the Exoclock project. They have a really nice scheduler to help you pick which transits would be available from your location and with your equipment and they are building a database of verified observations.
You can access that database programtically and there are even python code snippets for doing that here www.exoclock.space/database/planets

NASA also have an exoplanet database and details of its API are here exoplanetarchive.ipac.caltech.edu/docs/program_interfaces.html
That's probably a more complete database.

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