Problem
Splitting a grocery receipt or a restaurant bill between several people is slow, manual work: going line by line, working out who had what, then adding tax and tip. It falls hardest on students and people who live together and don't have a shared account, because they split bills like this again and again.
Users and jobs to be done
- Housemates after a grocery run: split one receipt fairly without a shared account.
- Students after a meal out: everyone pays exactly their share, tax and tip included.
- Whoever paid: send each person their total straight from their phone.
Decision log
| Decision | Why |
|---|---|
| Fix the money maths before touching the design | The first version rounded each person's share on its own, so three people added up to $50.32 on a $50.31 bill, and switching tax on without marking items could make the tax vanish. I added tests for the maths first. |
| Spare pennies go to the first person in the list | Shares always add up to the exact bill. Simple and predictable. |
| Mocked two options per screen, then picked one each | Items became a receipt-style list, Assign kept item cards with tappable faces, and Summary became big totals that expand. |
| Share through the phone's share menu | People send results in chat apps; it falls back to copying text where there's no share menu. |
| Switched receipt reading from Groq to Gemini, fastest model first | Groq's model was retired and its replacement misread long receipts. Gemini models are tried in order within free limits. |
| "Check sale prices" reminder after a scan | The fast models can read the original price on discounted lines. |
Results
- Live at billsplitter.yashchanne.com
- Passed a full new-user run-through in light and dark mode
- About 1,040 free receipt scans a day across the Gemini models
- 450+ bills split
What I'd do next
Bring the Scan screen up to the new design, then test a person-first Assign screen against the item-first one to see which is faster.