Modernizing a Legacy Mobile Application for Fuel Order Management

Client: Confidential Enterprise B2B Payment Services Organization – FinTech
Technologies: NativeScript, Ruby on Rails, iOS/Android, API Development

The Challenge

A fuel management organization operating within a highly regulated industry engaged Keyhole Software to modernize and enhance an aging mobile application originally launched in 2019. The app enabled authorized users to view, approve, or dispute fuel orders while accessing port location data—all from a mobile-optimized platform integrated with a larger enterprise system.

Although functional, the mobile app had not been updated in several years. The client required improvements to user interactivity, new backend capabilities, and readiness for re-deployment to public app stores.

Our Approach

Keyhole Software provided a senior consultant to lead the modernization effort, replacing the legacy NativeScript framework with Flutter, a cross-platform mobile UI toolkit ideal for building performant, native-like applications from a single codebase. This senior consultant to work directly with the client’s development team to improve the mobile experience while maintaining system continuity and backend security.

Project highlights included:

Rewriting the application in Flutter and Dart, delivering a responsive, modern mobile UI that supports both iOS and Android devices with a single codebase.
Extending backend functionality by updating the existing Ruby on Rails system, including upgrading the Rails version and creating new API endpoints to support comment tracking on fuel order actions.
Enabling contextual user input, allowing authorized users to leave comments on orders—both when viewing and when approving, disputing, or reversing actions across all order states.
Maintaining secure integration with the enterprise system through RESTful APIs, ensuring real-time order status synchronization and user authentication.
Configuring CI/CD pipelines and deployment automation using Fastlane, streamlining the delivery of production-ready builds to the Apple App Store and Google Play Store

Results

Modernized Mobile Experience: The app was fully rewritten in Flutter and re-released on iOS and Android platforms, improving UI performance and long-term maintainability.
Expanded User Capabilities: New features such as commenting on orders and actions enhanced transparency and collaboration across teams.
Improved System Integration: The Rails API was updated to support new workflows while maintaining compatibility with the broader enterprise environment.
Future-Ready Architecture: Flutter’s flexible framework and the updated backend architecture set the stage for future enhancements without costly rewrites.
Enhanced Workflow Transparency: Users can now add context to actions through comment support, improving collaboration and accountability.
Future-Proofed Architecture: Rails backend and API layer upgraded for long-term support and ease of future enhancements.
Cross-Platform Accessibility: App republished and made available to mobile users on both iOS and Android.

Key Takeaways

This project exemplifies Keyhole Software’s ability to revitalize legacy mobile applications by combining modern frameworks like Flutter with secure backend enhancements. Our team delivered a cross-platform, production-ready app that meets today’s performance standards while preserving integration with critical enterprise systems.