Rebuilding a Fintech Mobile App: From Vendor Transition to Successful Market Launch

Published on July 29, 2025

Introduction:

In our previous blog From Unknown Territory to Project Win, we shared our experience exploring the problem space, developing and submitting a proposal for a New Product Development, and ultimately securing the client's trust to win the project. In a subsequent blog From Project Win to AI-Assisted Product Engineering, we discussed how that initial vision gradually started taking shape and moving toward implementation. This blog covers a Banking Mobile App development project that we took over from an existing vendor and the process involved in that transition.

In the fast-paced fintech environment, particularly for consumer-facing mobile apps, taking over an existing development project presents significant challenges. Our main priorities throughout this transition included maintaining customer trust and user experience, ensuring continued regulatory compliance across all banking standards, aligning development efforts with the client's strategic objectives, and successfully meeting their key business goals within the expected timeline.

This approach aligns well with one of our execution approaches – Product Takeover and Acceleration Model (OPD – Execution Approach from Idea to Exit). At SwaaS, we work beyond just building products from scratch (Ideation → MVP → Scale → Exit). We also focus on rescuing and accelerating existing development projects that need fresh direction or enhanced momentum.

The Opportunity:

Through our partner, we were approached by a Middle Eastern bank to takeover their mobile app development from the existing vendor and accelerate the launch of their digital experience. The bank had invested considerable time and resources into a partially completed Flutter Mobile App and a Java-based middle-ware system that would integrate with APIs from a Fintech framework as well as the Core Banking system. During Phase 1 development, the bank faced ongoing challenges with extended agile cycles and release timelines. This created delays in meeting the bank's planned Go-Live schedule.

During our initial conversations, we learned that the planned roadmap had been delayed by months and was riddled with integration issues. We recognized this wasn't simply another mobile app development project – we were essentially working against a tight deadline with limited room for error. Given that the Go-live date had already been finalized, responding quickly to business requirements became critical. The bank needed a vendor who could deliver quality results within extremely tight timelines.

We presented our approach, timeline, and pricing structure considering all the factors discussed above. Given the constrained timeframes, we could only allocate a brief period for Discovery, Knowledge Transfer, and Takeover activities. After rounds of review and discussion aroud our proposed approach, budget and timeline we secured the project and began this challenging journey. Our experience became a comprehensive effort to take over a partially completed mobile fintech application, thoroughly understand the existing codebase and architecture, and then re-engineer the solution while building upon the current foundation to meet the bank's requirements and timeline.

The Scope and Objectives:

Our strategic priority was to take over the existing Flutter Mobile App and Java-based Back Office foundation developed by the previous vendor and transform them into production ready systems – a consumer-facing Banking Mobile App and an administrative Back Office for bank admins. The scope involved ensuring all components functioned seamlessly and met launch standards, covering everything from user interface design and system integrations to the overall consumer experience.

The critical challenge? We had only three to four months from project kick-off to launch, including a shorter discovery phase. With time already working against us, we needed a well-structured agile methodology, efficient execution, plus a thorough understanding of both the technical requirements along with specific challenges and regulatory nuances that come with the banking domain.

The Journey: From Rescue to Takeover and Delivery

As mentioned earlier, our Product Takeover and Acceleration Model is designed to efficiently Discover, Assess, Stabilize, Scale, and Implement applications that are mid-flight or at risk. We applied a structured three-stage approach to this Fintech Mobile App rescue and delivery process.

Discovery and Strategic Approach Definition:

While securing the project was an important milestone, our actual work began with a focused discovery phase designed to revisit and refine the requirements, establishing a solid foundation for moving forward. This stage proved essential in setting up the groundwork for our subsequent steps and overall project success. We started by reviewing the brief requirement and specification document provided by the client, which outlined high-level functionality details and API information. We then conducted a comprehensive two-week requirement understanding session that brought together stakeholders from the bank, fintech partner, and our development team. This collaborative effort included representatives from business, technical, and compliance departments to ensure all perspectives were considered.

We conducted a thorough review of the Figma designs and performed a detailed functional walkthrough of the requirements following the user journey flow. During this process, we carefully documented the functional requirements, non-functional requirements, and regulatory compliance needs. This comprehensive approach helped us ensure that no critical elements would be missed or overlooked during the development process.

We then moved forward with feature prioritization, collaborating closely with business decision makers to identify essential features and establish their priority levels for the initial launch. Following this, we compiled a list of nice-to-have features that could be prioritized and implemented in the future releases. This prioritization exercise was designed to focus on delivering the most critical functions to consumers in the initial launch while working within the three to four-month timeline constraints.

We summarized the session by creating a draft roadmap that outlined feature priorities, detailed user stories, and the corresponding sprint cycles. Given the tight timeline constraints, we designed a parallel development approach where the Back Office and Flutter teams could work simultaneously, focusing on the complementary aspects of their respective system requirements and deliverables. We also outlined our integration approach, testing methodology, user review processes, and deployment approach to ensure all teams had clear direction. After thorough discussion, we reached an agreement that infrastructure setup and security testing would remain the client's responsibility, allowing our team to focus on application development and delivery within the short timeline.

While the requirement sessions and strategic roadmap finalization were taking place, our tech team was working in parallel with the client to set up the Development, Staging, and Production environments. Simultaneously, the tech team was conducting a thorough review of the existing codebase from the previous vendor, examining both the Flutter App and the Java-based back-office middleware to understand the current state of development.

Development: The features Implementation

A well-defined roadmap with clear prioritization enabled us to proceed with sprint-based feature development. One of the most significant challenges we faced was understanding the complexities of the banking ecosystem. This particularly involved creating seamless integrations between fintech and core banking APIs through the Back Office system. We also needed to deliver appropriate consumer experiences in the Flutter Mobile app. During the early stages of development, several fundamental challenges emerged. The most prominent was navigating a complex API ecosystem. Understanding and working with the fintech framework APIs and core banking system APIs proved to be a substantial undertaking. This required us to decode authentication protocols, identify correct endpoints, and implement proper error handling mechanisms across multiple integrated systems.

Since this was a banking mobile app designed for end customers, maintaining UI/UX consistency was crucial. We needed to ensure that the user experience remained seamless and intuitive throughout the application. Converting designs from Figma into a functional mobile app required careful attention to detail. Flutter proved to be an excellent choice for this transformation, allowing us to convert static designs into pixel-perfect interactive experiences. Flutter's cross-platform capabilities allowed us to deliver a consistent experience for both Android and iOS users. Having a single codebase facilitated faster development iterations, more efficient testing processes, and coordinated functionality releases across both platforms.

During the initial weeks of development, our testing team worked in parallel to define comprehensive test cases based on the established roadmap, prioritized user stories, and requirements. We developed detailed test cases that covered functional requirements, design specifications from Figma, and banking compliance standards. Simultaneously, we collaborated with both the bank's team and the fintech framework providers to set up test accounts, create appropriate user profiles, and generate relevant transaction data needed for comprehensive testing.

By the end of the third week of development, we had completed several work packets that were ready to be tested and certified for user review. We executed test cases aligned with functionalities for both the Back Office and Mobile App, while also focusing on critical aspects such as response times, security measures, and overall app stability. Issues identified during testing were addressed by the development team, and then reverified to ensure proper resolution before final approval.

Our DevOps team established a well-defined CI/CD process for code deployment from Development to Staging to Production environments. While the client managed the actual environments and infrastructure, our responsibility was limited to code deployment through our established CI/CD pipeline, ensuring smooth releases across all stages.

Validation and Production Deployment:

Working within the timeline constraints, we successfully delivered the first expected milestone within the planned three to four-month timeframe. We then moved forward with a closed user group live deployment to test the application in a real-world environment. We initiated this phase with comprehensive user testing, involving the client's internal teams along with a select group of participants who closely represented their target consumers. The feedback we received from this testing phase provided valuable, practical insights into user behaviour and how people interacted with the app in real scenarios.

Issues identified during testing were thoroughly discussed, reviewed, and resolved. We categorized the issues by their source - whether they were API-related problems or Mobile App-related issues. Representatives from the Core Banking API team, Fintech Framework API team, and our Back Office and Mobile App development teams all played essential roles in addressing issues within their respective domains. Our primary focus was on fixing bugs, enhancing performance, and resolving any problems that could potentially disrupt the user experience. Every issue discovered during the testing phase was carefully tracked, prioritized, and resolved while maintaining system stability throughout the process.

Once development was complete and user certification was obtained, our focus shifted towards the security check. Certified security experts performed a thorough Vulnerability Assessment and Penetration Testing (VAPT) to ensure the application could withstand real-world security threats. This security assessment was managed by the client's team. Any security gaps or vulnerabilities identified during the VAPT process were discussed, carefully reviewed, and quickly addressed.

Finally, we worked closely with the client's infrastructure team to plan and execute the production deployment. Following our established CI/CD process outlined earlier, we performed the final code push after all the VAPT issues had been resolved and verified. The final step involved conducting comprehensive performance testing to validate that the system could effectively manage the expected user traffic volumes and consistently deliver fast and reliable responses.

Current State: Go-Live, Adoption and Key Success Factors

The platform received positive feedback from its initial launch. Within a few months of going live, the mobile app is now being used by more than 15,000 active users. We are currently working on developing the nice-to-have features that were identified during our initial prioritization phase. The bank has also put plans in motion to transition from their legacy mobile app to this newer version soon.

Beyond technical metrics, the project delivered significant business value for our client. The strategic decision to enhance and build upon existing technology assets rather than starting from scratch proved to be highly effective. This approach enabled us to deliver quality results within the challenging timeline constraints while preserving and maximizing the value of the client's previous investments.

Strong collaboration with the client's team proved essential throughout the entire project. We maintained regular communication channels, provided transparent progress reporting, and engaged in collaborative problem-solving approaches that maintained alignment and confidence throughout the intensive development period. Our structured communication framework included daily status reviews, bi-weekly sprint reviews, and iterative development that enabled us to incorporate feedback efficiently and adjust priorities as needed based on evolving requirements and testing results.

Conclusion: Rescue is a discipline

Many development teams face challenging situations where projects don't progress as expected, timelines stretch beyond plans, and stakeholder confidence is put to the test. These situations often involve more than just technical issues - they can affect team morale and project momentum in ways that go beyond code and technology choices.

Rescuing a product involves more than just identifying and fixing technical issues during extended development sessions. It's about rebuilding confidence - in the project vision, in the team's capabilities, and in the possibility that what seemed unachievable yesterday can become a success story tomorrow.

Our Product Takeover and Acceleration Model isn't just a service; it's a lifeline.

Whether you're working with inherited codebases, managing evolving stakeholder requirements, or navigating complex vendor transitions; these are common challenges in product development. We understand these situations and have experience guiding projects toward successful outcomes.

Our teams focus on both technical excellence and team collaboration to ensure everyone stays aligned and motivated throughout the development process. Successful products are built by teams that feel confident in their approach and direction.

Ready for a Rescue?

If you're managing a mobile app project that's experiencing delays or technical challenges, starting over isn't always the best solution. Let us help you get back on track with focused expertise, efficient process, and clear direction.

Connect with SwaaS IT Solutions to learn how we can help accelerate your product development and achieve your launch goals.