Lazy Susan
The person who paid should not also have to do the maths.
Take a photo of the receipt. An open model reads every line on your phone, the receipt's own arithmetic checks what it read, and you tap who had what. Tax, service and tip are shared in proportion. Paste the result in the group chat.
No sign-up, no upload, no typing in prices. Works offline once it has loaded.
The reader is Donut, an open-weight document model from NAVER Clova (MIT licence), trained on receipts. When its read does not add up, Florence-2 (Microsoft, MIT licence) takes a second look, and the read that adds up wins. The first photo downloads Donut, 219 MB, once; Florence-2 (266 MB) only if a receipt needs it.
Who had what?
Pick a person, then tap their items. Tap again to undo. Shared plates: tap them for each person. Lines nobody claims are split between everyone.
The split