While building my Cost of Living Calculator, I realized I'd like to allow sharing calculations via a direct link. Since I went really lean on the app development and didn't build a backend, there was no way I could store calculations in a DB.
Each calculation is essentially a finite number of parameters (number of family members, times a week you eat out, etc) and a set of cities it's applied to.
So I decided I'd pack these values directly into a URL and read them back once this link is opened.