One person pays it and everyone else uses an app called Swish on their mobile phone to transfer money directly to that person’s bank account. It has become quite common amongst my friends to do a similar thing for bills in restaurants, for example. Hell, when a friend left my last job everyone Swished me money and I bought the leaving present.
Swish depends on a “Mobile Bank ID” that you download from you online banking and install on your phone. It has its own app that is used to verify any action that requires a Mobile Bank ID confirmation. It is used in quite a few different places. For example Försäkringkassan, the Social Security agency, uses it when you use their app to check various things, the healthcare system uses it when you log in to their system to book doctor appointments etc and it is even used when purchasing online using a credit card as an extra layer of security (meaning you can’t use a stolen credit card online unless you have also got the phone, the PIN to the phone and also the PIN to the Mobile Bank ID app).
Frankly it is all rather handy.
ETA:
Further explanation: you register for Swish via your online banking and specify (IIRC) the phone number it works with. Then people only need your phone number and not your bank details to send you cash. Any business that doesn’t have credit card payments set up will have a corporate Swish account that works with the Swish app but isn’t a true phone number. You don’t tend to see this that often though as most businesses simply accept credit cards. Oh and that pizza? It will have been bought online with someone using the credit card. And we pay people a fair wage here so you don’t have to tip.
Also, I go to a jazz club called Lönnkrogen here in Stockholm. They encourage the use of Swish to give money to the band. They also do a jokey thing where they have one song that they’ll play and then stop, put a mobile phone up to the mic and then don’t play until they hear the push notification that someone has Swished them.