Mobile App / Fintech

From spreadsheets to software: turning shared financial friction into a system of trust.

A collaborative mobile platform designed to eliminate social awkwardness around shared money through automated balances, transparency, and frictionless pairing.

Client
Combim
Timeline
2025
Scope
UI/UX, Digital Design, Icon Design, Motion Prototype
Squad
Product Manager & Product Designers

Context

Couples and families sharing living expenses frequently depend on spreadsheets and physical notebooks, tools never engineered for this dynamic. They fail to compute proportional splits, do not track who paid what, and cannot manage recurring expenses.

Through empathy mapping and participatory research, we discovered that the real issue was not just organization, but the emotional friction and hesitation around settling debts.

66.7%

rely on notebooks or spreadsheets to track shared costs

60.0%

have partial or zero clarity on individual vs. joint expenses

Authentication & Setup

Two-sided account pairing without fragmented invites.

Combim authentication and dual-member onboarding flow screens

Challenge

01

Misfit tooling

Spreadsheets and paper notebooks cannot compute automatic splits or track payer accountability in real time (44.4% and 66.7% usage).

02

Lack of transparency

The majority of cohabitating pairs lack a clear distinction between what constitutes individual versus joint household expenses (60.0%).

03

Social friction over trust

Chasing or being reminded about split money is an uncomfortable, repetitive chore (77.7%) — the core issue is interpersonal trust, not just bookkeeping.

Flow 01

Dual-branch entry & debt settlement

A unified creation trigger branching into either a multi-step shared expense setup or a one-tap debt payoff.

Combim Flow B: Dual branch entry and debt settlement diagram
Branch A

Debt Settlement (Quitar Dívida)

A direct path designed for speed. Automatically calculates pending balances between users and registers repayments without forcing extra form fields.

Branch B

Shared Expense (Adicionar Despesa)

A structured 2-step wizard separating financial parameters (category, installments, payer) from final split confirmation to prevent input fatigue.

Flow 02

Expense logging & transaction management

From first entry to granular editing, streamlining how users record, review, and adjust shared costs.

Empty State
01

Empty State

A clean onboarding view encouraging first-time logging with clear guidance.

Expense Ledger
02

Expense Ledger

A unified timeline tracking recurring items, individual shares, and quick deletion actions.

Expense Details & Edit
03

Expense Details & Edit

Intuitive modal to configure payer distribution, category tags, and split ratios.

Micro-interaction & Craft

Swipe-to-delete with tactile feedback and zero layout jumps.

In fast-paced expense logging, removing accidental duplicates or cancelled transactions should not require entering a sub-menu. We designed a gesture-driven swipeable card mirrored directly from our React Native codebase to the web.

✦ Built with elastic resistance, threshold-triggered confirmation, and physics-driven spring animations.

← Drag to interact / test swipe
04ABR
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DrogasilAndreza pagou
R$ 37,20Parcela 1 de 8

Results & Status

Live testing with real households is currently awaiting final clearance from UFRN's ethics review board. Validation to date has centered on technical delivery and rigorous process governance:

Technical Delivery

7 Native Navigable Flows

Fully functional on physical devices with React Native, Expo, and TypeScript. Supported by a 32-token architecture (16 color, 8 typography, 8 spacing) synced between Figma and code.

Process Rigor

3-Tier Review Cycle

Iterative reviews moving from peer Product Designer alignment to PM discovery reviews, concluding with PM validation directly in the codebase.