I remember when remove.bg dropped, to a collective gasp. Give it a photo, and it automatically removes the background with no additional input or worked needed. Friggin cool. Now the website gives you “1 credit” to do that job, which you need to sign in to get. After that, you pay. I don’t begrudge that, building and maintaining software costs money, although maybe they should have just opened with that system.
But now I see there is an open-source library, background-removal-js, with a hosted demo which does the same thing for free again. I can’t speak to the speed or quality comparisons, but in the few images I tested across both, the free thing seemed fine.
The open-source library is from a for-profit company, so maybe don’t hold your breath on this demo being available free forever, but the fact that it’s open-source now means the code to do this client-side will always be floating around the great code ether.