Which database of celestial objects do stargazing apps use? Stargazing apps such as Star Walk must have a database with a list of celestial objects, their names and details and each of their celestial coordinates.

I am interested to know which database these apps use as I am looking to build my own stargazing app for a computing project.

It would be great if someone could help me with this.

Thanks!
The Hipparcos is probably all that's really needed.  A lot of them add in portions of the Tycho catalog as well.  But even the Hipparcos catalog has more stars than what most armatures will need, and it's generally impractical memory wise to use the whole thing.  To really go crazy, a torrent for the NOMAD catalog is available.  All of those list only individual stars.  For things like galaxies and nebula the NCG catalog should do, but there are also the Index Catalogue, and Hershel Catalogs.  The most popular catalog would be the Messier, which has no official distribution sources (that I know of), but databases are available if you search this one for example.

If you don't care about the original sources, Stellarium has their star catalogs on their wiki.