Mr. Splitter
Bill splitting · LINE LIFF × PWA
Stop chasing people for money — from LINE group chat to settled, in one flow
Group trips, dinners, and shared bookings always leave the same headache: who paid what, and who still owes whom. Most bill-splitting apps are either too bloated or too niche for anyone to bother installing. Mr. Splitter aims to eliminate that friction — run it straight from LINE, no install required.
Built on LINE LIFF so group members open the splitter directly inside the chat thread — zero install. Core flow is three steps: create a bill, add items, read the settlement. A greedy algorithm minimises transaction count, collapsing an N-person debt graph into the fewest possible transfers. Packaged as a PWA too, so it works standalone when LINE isn't in the picture.
Add a bill, invite members, log expenses, get per-person totals in one tap
From creating a bill to seeing per-person totals takes just a few taps. Supports equal split or custom amounts. All expense items are listed clearly, and members can check progress anytime inside the LINE chat — no app switching needed.
LINE LIFF vs standalone app
LINE has over 20M MAU in Taiwan. Asking users to install another app in a group context halves conversion. LIFF keeps the experience inside LINE — users never leave the chat to complete the full split flow.
Minimum-transactions split algorithm
Naively "everyone pays the payer" is simple but generates too many transfers. A greedy strategy sorts net balances and matches the biggest debtor to the biggest creditor each round, reaching the theoretical minimum number of transactions.
PWA as fallback channel
For non-LINE users or desktop scenarios, the PWA offers an 'add to home screen' experience with offline-cached core pages. Mr. Splitter isn't LINE-only.
Algorithm does the math; LINE Pay closes it out
The settlement screen compresses N-way debt into the minimum number of transfers and shows exactly who pays whom. Each entry has a LINE Pay shortcut, or share the settlement link back to the group — no screenshots or manual math.
What this build would use
- Next.js 15
- LINE LIFF SDK
- PWA / Service Worker
- TypeScript
- Vercel