PayBro

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  Mascot/App Icon

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Inspiration

Group expenses in India follow a familiar pattern: one person pays, everyone else promises to settle later, and the payer is left chasing friends for money — or quietly writing it off.

Existing tools make this worse. Logging a single dinner in Splitwise takes six steps: select a group, enter the amount, choose a split type, adjust members, add notes, save. That friction means expenses go unlogged, debts go forgotten, and friendships absorb the cost.

Meanwhile, the two rails needed to solve this already exist and are universal in India: WhatsApp and UPI. What was missing was the input layer. Typing is the bottleneck; speaking is not.

PayBro removes the form entirely. You say: "Paid 1850 at Toit with Rahul, Aman and Sneha — Aman only had beer for 400." One sentence produces a fair, itemized, settled split.

What it does

PayBro is a voice-first expense splitter. One spoken sentence becomes settled debt:

1. Speak. Hold the mic and describe the expense naturally, in English or Hinglish, including exceptions — "Priya didn't drink," "Aman only had beer for 400."
2. AI structures it. Speech is transcribed on-device and parsed by Gemini into structured output: title, total, and per-person amounts, with exclusions and uneven shares handled correctly. Every result is validated so the splits reconcile exactly against the total before anything is saved.
3. Contacts resolve privately. Spoken names are fuzzy-matched against the local address book. Contact data never leaves the device.
4. Settlement is one tap. Each participant receives a pre-filled WhatsApp message containing a standard UPI intent link. Tapping it opens any UPI app with payee, amount, and note pre-filled. Money moves directly between bank accounts; PayBro never holds funds.

The product is deliberately constrained to three screens: Home (net balances and activity), Voice AI (capture and confirmation), and Profile (payment and subscription settings).

How we built it

• Flutter — single codebase, feature-first clean architecture, Material 3.
• RevenueCat — the complete monetization layer. The free tier allows 15 voice splits per month, tracked locally. The entitlement check runs before the microphone activates, so the paywall appears at the moment of highest intent and no AI cost is incurred for blocked users. Pro (₹299/month) unlocks unlimited splits, receipt OCR, and smart reminders, with entitlements restored across devices. The paywall itself is RevenueCat's native PaywallView.
• Supabase — phone OTP authentication behind an anonymous guest mode, so first-time users get full value before ever signing in. PostgreSQL with row-level security backs an offline-first sync engine: SQLite is the local source of truth, and a queued sync layer reconciles with the cloud when connectivity returns.
• Gemini via OpenRouter — structured JSON output for parsing, with provider fallback. On-device speech recognition keeps the voice pipeline free.
• WhatsApp and UPI deep links — pure client-side URL schemes. No payment infrastructure, no compliance surface, no marginal cost per settlement.
• Local notifications — a single reminder if a split remains unsettled after 48 hours, with a ready-to-send follow-up attached.

Challenges

• Fairness is a parsing problem, not a division problem. "Aman only had beer for 400" requires excluding him from the shared pool, not assigning him a flat amount. We enforce total reconciliation before persistence and provide an inline editor as the human override.
• India's SMS regulation. OTP delivery to Indian numbers requires government DLT registration with multi-week lead times. We designed around it: guest-mode onboarding ensures authentication never blocks the core value.
• Name resolution. Spoken names rarely match contact entries exactly. We tuned an on-device fuzzy matcher with phone normalization to resolve them reliably without any data leaving the phone.

What we learned

• A paywall converts best when it is invisible until the moment of intent. Fifteen free splits builds the habit; the gate only appears when the habit is formed.
• Voice is not a novelty when the alternative is six form fields. It is an order-of-magnitude reduction in friction.
• In India, a WhatsApp message with a UPI link outperforms any in-app payment flow — it meets people where they already settle up.

What's next

• Receipt OCR via Gemini vision — photograph the bill instead of speaking
• WhatsApp-native authentication, replacing SMS OTP at a fraction of the cost
• Multi-currency splits for group travel
• A home-screen widget surfacing the net "owed to you" balance

Built With

• android
• artificial-intelligence
• dart
• deep-links
• fintech
• flutter
• google-gemini
• in-app-purchases
• mobile
• offline-first
• openrouter
• postgresql
• revenuecat
• speech-to-text
• sqlite
• subscriptions
• supabase
• upi
• whatsapp