Reflecting on our journey: Achievements and valuable lessons in building our credit card transaction processing system

Man holding credit card
Sep 15 2023
Business News

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We couldn’t be more excited to announce the successful completion of our most recent endeavour – a cutting-edge credit card transaction processing system! Over the course of this incredible journey that began over a year ago, we faced numerous challenges; from navigating the merger of companies to working with globally dispersed teams (each with their own tech stacks and cultures). Despite these hurdles, we persevered and triumphed. We want to take a moment to reflect on what we’ve built, what we’ve achieved, and the invaluable lessons we’ve gained with our internal teams and a broader audience.

What we have built:

🏆 Monolithic to Microservices: 

We’ve undertaken a major shift in architecture, migrating parts of a monolithic core service into horizontally scalable Java microservices. This transition has brought unparalleled flexibility and efficiency to our system.


🏆 Robust Transaction Engine: 

We’ve developed a robust and efficient transaction engine capable of processing millions of credit card transactions per day, ensuring the utmost reliability and performance for our clients.


🏆 Reactive Architecture: 

To ensure real-time responsiveness and optimal resource utilisation, we embraced a reactive architecture powered by Spring Boot and R2DBC. This technology stack has empowered us to handle high volumes of transactions with ease.


🏆 Real-time Monitoring: 

The system includes real-time monitoring tools to provide instant insights into transaction status and performance, giving our clients peace of mind.


🏆 Real-time Cutover and Fallback:

Instant switch over between the old and new systems had to be built into our system design to ensure continuous operation for our customers during the migration process which meant significant complexity in data consistency between our new services and the legacy solution.


We have also employed and continue to utilise the following methodologies and tools, instrumental in enabling quicker iterations and expediting our time-to-market:


⚒️ Agile Development: 

Throughout the project, we adhered to Agile methodologies, allowing us to adapt to changing requirements and deliver incremental value to our clients.


⚒️ Continuous Integration and Continuous Deployment (CI/CD): 

We’ve integrated CI/CD pipelines into our development process, enabling us to rapidly develop, test, and deploy new features and updates with confidence.


⚒️ AWS Cloud Infrastructure: 

To enhance scalability and reliability, we’ve leveraged the AWS Cloud to host our containerized microservices. This cloud-native approach ensures high availability and robustness.


What We Have Achieved:

Our journey in building this credit card transaction processing system has been incredibly rewarding, and the results speak for themselves:


🚀 From Scratch to Success: 

We embarked on this journey by designing and building the entire project from scratch. This greenfield approach allowed us to envision and create a system perfectly tailored to meet the evolving needs of our clients.


🚀 Reduced Latency: 

Through meticulous optimization and the adoption of reactive architecture, we’ve significantly reduced end-to-end processing latency. Transactions now flow seamlessly, providing quicker responses to our clients and their customers.


🚀 Enhanced Scalability: 

One of our most significant achievements has been the enhancement of scalability. Our system can effortlessly accommodate surges in transaction volumes, ensuring uninterrupted service during peak times.


🚀 Large scale, complex Seamless Migration: 

During the project, we successfully migrated our existing Customer’s credit card tokens including all their complex use cases from one payment processor to another, all while keeping the old payment rail running. This complex operation involving millions of customer accounts required precision and finesse, ensuring a smooth transition for our clients without disruptions.


Our accomplishments underscore our commitment to innovation and customer satisfaction. It’s a testament to the dedication, expertise and adaptability of our teams.


What We Have Learned:

📚 Adaptive Planning: 

We’ve learned that in complex projects, it can be challenging to estimate the scope of work accurately. To overcome this, we’ve emphasised the importance of keeping our project plans updated and maintaining open communication with our stakeholders. Flexibility and adaptability have been our allies.


📚 Teamwork: 

Our success wouldn’t have been possible without our dedicated and talented teams. We’ve learned that fostering a collaborative and inclusive work environment is key to achieving exceptional results. Managing internal team dependencies is crucial in large-scale projects. Effective coordination and collaboration among different teams within our organisation have been essential to ensure smooth development and deployment processes.


📚 Flexible Architecture: 

By spending the time up front in segregating the responsibilities as much as possible within our core systems so they are as independent as possible and by providing flexible facades to our partner’s systems we were able to adapt rather than having to rework our Architecture as changes were required and new integration complexities were uncovered in-project.


📚 External Party Dependencies: 

We’ve encountered scenarios where our project was reliant on external parties, such as the new payment processor partner. This experience has taught us the value of dedicated point of contact, reliable communication, and contingency planning to mitigate external dependencies.


📚 Customer Communications: 

Effective and transparent communication with our customers has been pivotal to the success of this project. Keeping them informed about progress, changes, and potential disruptions has fostered trust and strengthened our client relationships.


📚 Guidelines and Education: 

We’ve recognized the importance of establishing clear guidelines and educating team members about best practices. This has not only improved the quality of our work but also enhanced our team’s ability to adapt to new technologies and methodologies.


📚 Following Standards: 

Compliance with industry standards like ISO 27001 and PCI DSS has been a non-negotiable aspect of our project. Upholding these standards ensures the security and integrity of financial data, and we’ve learned that strict adherence is fundamental.

In conclusion, our journey in building this credit card transaction processing system has been more than just a technological feat. It’s been a lesson in adaptability, collaboration, communication, and commitment to excellence. We’ll carry these lessons forward as we continue to innovate and provide cutting-edge solutions to our clients. Thank you to everyone involved in this incredible journey!

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