A small expense splitter for a group trip or a shared flat: track who paid for what, see each person's balance, and settle up with the fewest transfers.
- Groups of members, each with a share token.
- Expenses: a payer, an amount in cents, and who the cost is split among.
- Balances: what each member paid minus what they owe.
- Settle up: the minimal set of transfers that zeroes every balance.
- CSV export of a group's expenses.
- A CLI (
groups,balances <group>,export <group>) alongside the web page and API.
Bun, TypeScript, Hono, bun:sqlite. No build step for the web page
(public/index.html is served as-is).
src/money/ integer-cents math: split, format, parse
src/auth/ token lookup and permission checks (protected path)
src/db.ts schema
src/*.ts domain logic (expenses, balances, csv)
src/routes/ HTTP handlers
src/server.ts Hono app + Bun.serve entrypoint
src/cli.ts splitbill CLI
public/ the web page
tests/ bun:test suite
See AGENTS.md for conventions and what's protected.
DEMO.md explains how to run the factory against a disposable splitbill-demo copy. Never run it
against this repo. Each teaching session's starting state is the checkpoint/<id> tag in
splitbill-demo that factory/teach/sessions.json names. The 01-boundary … 06-delivery
branches and checkpoint/0N-* tags in this repo are legacy (they use the old lesson numbering) and
are kept only for anyone who already cloned them.