Great questions! My tech stack is a bit unconventional. For example, my primary db is Baserow - basically an open-source Airtable. The app was written with a combination of Swift and Objective-C, so iOS native, though I also plan to release an Android version. For the UI, I prototyped in Figma and storyboarded it (not a huge fan of writing interfaces).
Probably one of the biggest challenges has been collecting enough data so that users in most locations can log on and see food trucks near them.