Build a Bill Splitter App for Roommates (2026)

Splitting rent, groceries, and the never-ending utility bills with roommates is annoying enough without wrestling a one-size-fits-all app into shape. Instead of downloading yet another tool, you can build your own bill splitter — tailored to your apartment, your roommates, and the way you actually settle up.

Why build it instead of downloading one

If you search for the best app for splitting bills with roommates, you’ll find plenty of options. Most are close but not quite right: they nag you to invite people, lock the useful parts behind a subscription, or assume everyone splits everything evenly. Real households aren’t like that — sometimes it’s split by item, sometimes three ways on rent but two ways on the internet.

Auto is camera-first: you describe what you want, snap a photo, and it builds you a personal mini-app — a “Frame” — around it. Building your own roommate expense tracker app means it fits exactly how your place works, and it takes minutes. People have already built Frames like Bill Splitter this way, so you’re not starting from a blank page.

Building your Bill Splitter in Auto

The fastest way in is to describe the job in plain language. A good first prompt covers three things:

1. What to capture — “Scan a receipt or utility bill and pull out the merchant, date, line items, subtotal, tax, tip, and total.”
2. How to store it — “Keep a scrollable history of past bills sorted by date, with a monthly spend summary at the top.”
3. How to split — “On each bill, let me add a tip and split the total between roommates — evenly, or by assigning items to people, including tax and tip.”

Snap a photo of a real receipt to test it, then refine. If something looks off, just say so in your next message — Auto edits the Frame in place.

How someone built theirs

One Auto user built exactly this, and their prompts are a useful blueprint.

They started broad: a Frame called “Receipt Scanner” that uses vision to extract structured data from a bill photo — merchant, date, itemized lines, subtotal, tax, tip, total — stored as a history you can scroll, with a detail screen for each receipt and a this month spend banner. Clean, card-based layout.

The first build hit a snag (a genuine error came back), so they asked Auto to fix it — and it did, no code required on their end.

Then came the part that makes it a split rent and utilities app: they asked for an easy way, on each bill’s detail page, to calculate tip and split the check — either evenly or by assigning items to specific people. A follow-up made sure the split accounted for tax and tip, not just the raw items.

Finally they tidied up: refreshed the name and description to match the new features, settling on a straightforward “Receipt Scanner.” A few messages, one working app, shaped entirely around how they wanted to split.

FAQ

Do my roommates need Auto too? No. You build the Frame for your situation. How you share the results — a screenshot, a total in the group chat — is up to you.

Can it handle rent and utilities, not just restaurant receipts? Yes. Any bill photo works, and you can split unevenly or assign specific charges to specific people.

What if my first version isn’t right? Describe the change and Auto edits the Frame. The user above fixed a build error and renamed theirs mid-build — refining is expected.