I built one in Haskell at my old employer as well that works pretty smoothly (the whole pkpass format is implemented on type level): https://github.com/tazjin/h

I built one in Haskell at my old employer as well that works pretty smoothly (the whole pkpass format is implemented on type level): https://github.com/tazjin/hs-pkpass https://github.com/tazjin/hs-pkpass Unfortunately the tool built around it never made it into production, marketing cancelled the project :(