splitbill

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.

What it does

• 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.

Stack

Bun, TypeScript, Hono, bun:sqlite. No build step for the web page (public/index.html is served as-is).

Layout

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.