Mobile Expense Report Management Application
About this project
This mobile application revolutionizes expense report management by eliminating the traditional paper-based process. Designed to simplify employees' lives and optimize accounting teams' work, it enables quick and intuitive expense entry directly from smartphones. Users can easily record their professional expenses in just a few clicks: date selection, establishment details, expense type selection from a predefined list, amount entry, and receipt photo attachment. The streamlined interface guides users through each step without technical complexity. The system integrates an intelligent approval workflow with clear visual statuses: pending processing, accepted but not yet reimbursed, or definitively reimbursed. Business rules are integrated (€20/day meal reimbursement limit, parking and toll restrictions outside working hours, breakfast allowed only if not included in hotel stay). For accounting teams, the application centralizes all requests with photographic receipts, facilitates batch validation, and automates reimbursement file generation. It significantly reduces input errors, lost receipts, and back-and-forth between employees and accounting, while accelerating reimbursement timelines.
Key Features
- Simplified mobile entry: Intuitive mobile interface for quickly recording expenses: date, establishment, expense type, amount, and receipt photo in just a few gestures.
- Integrated receipt management: Direct photo capture of receipts and invoices from the application. Secure storage and automatic association with corresponding expense reports.
- Intelligent approval workflow: Multi-level validation system with visual statuses: pending, accepted, reimbursed. Automatic notifications for each status change.
- Integrated business rules: Automatic application of company policies: reimbursement caps, time restrictions, authorized expense types according to professional context.
- Real-time tracking: Instant visualization of each reimbursement request status. Complete expense report history with filtering and search capabilities.
- Accounting management interface: Dedicated back-office for accounting teams enabling batch validation, data export, and automatic generation of reimbursement transfers.
- Automatic categorization: Intelligent expense classification by type (transport, dining, accommodation, supplies) with suggestions based on user history.
- Compliance control: Automatic verification of amounts, dates, and expense types according to internal policies. Non-compliance alerts before submission.
- Accounting export and integration: Automatic generation of export files compatible with accounting software. Possible integration with existing ERP systems.

Home
Initial application state before expense report entry

Expense Reports List
Overview of requests with visual statuses and amounts

Home with Filters
Home interface with filtering by status and period

Expense Report Creation
Complete entry interface: date, establishment, type, amount, and photo receipt

Expense report details
Detailed processing tracking with validation and reimbursement statuses

Navigation menu
Main navigation with access to different sections and user help

Expense Report Details
Detailed processing tracking with validation and reimbursement statuses
Challenges
The main challenge was the extreme time constraint and complete absence of budget: developing a comprehensive solution in record time without servers or financial means. It required ingenuity by maximizing free cloud tools and no-code platforms. The hybrid architecture combined Firebase, Vercel, and various free APIs, requiring deep expertise in their limitations. Each free service imposes strict quotas (requests, storage, bandwidth) particularly critical for receipt photos. Using no-code tools limited customization, forcing adaptation of business needs to technical constraints rather than the reverse. Synchronization between disparate services and designing an scalable solution without budget represented major architectural challenges.
Learnings
The most striking lesson was the relativity of technical means compared to the paramount importance of solving user problems. Technology, tools, or financial means are not essential: what matters is providing a concrete response to a real need, regardless of the means employed. Extreme budget constraints became a creativity catalyst, forcing exploration of alternative solutions often more elegant. Adaptability to technical limitations proved more valuable than mastering sophisticated tools. This project confirmed that an imperfect but functional solution delivered quickly is better than a perfect architecture never realized. Current free tools offer extraordinary possibilities: the barrier to entry is no longer technical or financial, but creative and methodological. Technology must remain a means to serve the need, never an end in itself.