Splitty

Split your expenses easily.

🚀 Try it live at splitty.arkapravo.in — no install needed.

What is Splitty?

Splitty is a lightweight, self-hostable web app for tracking shared expenses inside a group of people and figuring out the simplest way to settle up. Think of it as a focused, no-frills alternative to apps like Splitwise: you create a group, add the people in it, log who paid for what, and Splitty tells everyone exactly which transfers will leave the group square — using as few payments as possible.

What is it for?

It's built for the small, recurring situations where money gets messy:

• Trips and holidays — someone books the hotel, someone else covers dinner, a third person rents the car.
• Flatmates and roommates — groceries, utilities, that one big delivery, the new vacuum cleaner.
• Friend groups and meetups — one person tabs out at the bar and everyone Venmos them later.
• Couples and families — keeping a running tab on who paid for what without spreadsheets.

If you've ever ended a trip with a screenshot of a Notes-app tally and a vague promise to "sort it out later" — that's the problem Splitty solves.

What can it do?

• Email / password accounts with secure session cookies (JWT via jose, passwords hashed with bcryptjs).
• Expense groups — own and belong to as many groups as you like; Splitty remembers which one you had open last.
• Member management — invite existing users to a group by email; members can leave any group they don't own.
• Expenses — record amount, who paid, who added it, and free-form details. Owners can edit any row; members can edit rows they added or paid for.
• Lockable groups — owners can lock a group when a trip ends, freezing it as read-only.
• Multi-currency — pick from a currencies table per group; amounts render with the group's symbol (₹, $, €, …).
• Settle up — a greedy minimum-transfer algorithm shows the smallest set of payments that settles the group, and each transfer can be ticked off as paid.
• Profile management — change your name or password, or soft-delete your account.
• Light / dark theme out of the box.

How the settle-up math works

When you open a group's Settle up view, Splitty:

1. Sums every expense in the group.
2. Divides the total equally among current members to get each person's fair share.
3. For each member, computes balance = paid − share. Positive means they're owed money; negative means they owe.
4. Greedily pairs the largest creditor with the largest debtor, settles the smaller of the two amounts, and repeats until everyone is within half a cent of zero.

The result is O(n) transfers in the typical case rather than the naive O(n²).

Tech stack

Layer	Choice
Framework	Next.js 16 (App Router, React Compiler enabled)
UI	React 19, Tailwind CSS v4, shadcn/ui (base-lyra style), Phosphor Icons
Database	Neon serverless Postgres via @neondatabase/serverless
ORM	Drizzle ORM + drizzle-kit
Auth	jose (JWT) + bcryptjs + httpOnly cookie
Notifications	sonner (toasts)

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Getting started

Prerequisites

• Node.js 20+ and npm
• A Postgres database. The defaults assume Neon (the HTTP driver is wired up via @neondatabase/serverless), but any Postgres reachable via a connection string will work.

1. Install dependencies

npm install

2. Configure environment

Copy the example file and fill in your own values:

cp .env.example .env

You need two variables:

Variable	Required	Notes
DATABASE_URL	yes	Postgres connection string. For Neon use the pooled URL with ?sslmode=require&channel_binding=require.
JWT_SECRET	yes	At least 32 characters. Used to sign session JWTs. Generate one with openssl rand -base64 48.

The app throws at startup if JWT_SECRET is missing or shorter than 32 chars.

3. Set up the database

Drizzle Kit reads DATABASE_URL from .env via dotenv/config.

# Generate SQL migrations from the schema
npm run db:generate

# Apply them to the database
npm run db:migrate

# …or, for quick local iteration, push the schema directly
npm run db:push

Splitty looks up symbols from a currencies table at runtime (and defaults new groups to INR). Seed it with at least one row, for example:

INSERT INTO currencies (code, symbol, name) VALUES
  ('INR', '₹', 'Indian Rupee'),
  ('USD', '$', 'US Dollar'),
  ('EUR', '€', 'Euro'),
  ('GBP', '£', 'British Pound')
ON CONFLICT (code) DO NOTHING;

Use npm run db:studio to browse and edit data in Drizzle Studio.

4. Run the dev server

npm run dev

Then open http://localhost:3000, create an account at /auth/sign-up, and you'll land on the home page where you can create your first group.

NPM scripts

Script	What it does
npm run dev	Start the Next.js dev server
npm run build	Production build
npm run start	Serve the production build
npm run lint	Run ESLint
npm run db:generate	Generate Drizzle SQL migrations from schema.ts
npm run db:migrate	Apply pending migrations
npm run db:push	Push schema directly to the database (dev only)
npm run db:pull	Introspect an existing database into Drizzle schema
npm run db:studio	Open Drizzle Studio

Deployment notes

• The Neon HTTP driver works on the Edge runtime, but the routes here explicitly opt into runtime = "nodejs" to use bcryptjs. If you switch hosts, make sure Node-compatible APIs are available.
• Set DATABASE_URL and JWT_SECRET in your platform's secret manager — never commit .env. Rotating JWT_SECRET invalidates all existing sessions.
• Run migrations (npm run db:migrate) as part of your deploy pipeline.

License

Licensed under the GNU Affero General Public License v3.0 — see LICENSE for the full text.

In short: you're free to use, modify, and self-host Splitty, but if you run a modified version as a network service you must make your source available to its users under the same license.