[andrekandre]

(not the op so this is jme...)

  > Do you now have a BFF for each client type? Who owns it then ? Don't you now need more fullstacks ?

everyone has an opinion, but ime ideally you'd have 1 bff for all clients from the start

  > there's confusion. Now you have 2 sets of contracts (API-BFF, BFF-clientIOS, BFF-clientAndroid, ...). You now have more human synchronization overhead. Changes take longer to percolate throughout. More scope for inconsistencies.

yep, i have literally experienced the chaos this can cause, including the endless buzywork to unify them later (usually its unify behind the web/html bff which breaks all kinds of frontend assumptions)

  > Isn't is better to have the API team own the single source of ownership ?

it depends on what it means 'api team'... but ideally bff has its ownership separate from 'backend' wether that is in 'api team' or outside i think is less important ime

but... ideally this separation of ownership (backend backend, front end for backend) allows each to focus on the domain better without mixing up say localization in the lower level api's et

iow having a bff is sort of like having the view model as a server... that way multiple clients can be dead simple and just map the bff response to a ui and be done with it

(thats the ideal as i understand it anyways)