NTT DOCOMO migrates the backend system of the d-Barai application to AWS and implements CX improvement measures in a short cycle


We have been able to add and improve a lot of functionality in a short period of time, while keeping pace with an annual growth of about 10 million users, because we have more time to deliver new value to our customers by reducing the operational burden through the use of AWS.

Mr. Tetsuou Ohori
Manager in charge of Wallet Service, Product Design Dept.

NTT DOCOMO, Inc., which provides the d-Barai mobile payment service, has separated the back-end logic from the application and migrated to Amazon Web Services (AWS) to quickly release additional and improved features that are valuable to customers. The architecture has been redesigned with a focus on managed services, serverless, and containers. This allows for continuous feature additions and functional and UI improvements on a bi-weekly cycle, greatly increasing the speed at which the service evolves.

Delivering value to our customers quickly
Rearchitecting back-end systems

NTT DOCOMO's d-Barai service, released in April 2018, enables barcode payment, wallet, and payment history display via a smartphone application. Since then, the number of users has grown at a rate of more than 10 million per year, reaching 43.75 million by the end of March 2022. In order to provide a valuable customer experience, NTT DOCOMO is working to improve the usability of its applications and strengthen its infrastructure. In early applications, many of the services were implemented as application-side logic and tightly integrated with the core system through APIs. This made it difficult to add and improve service features on a short cycle, which required customers to update their applications after new features were released.
Therefore, we decided to speed up the functional improvement cycle by separating the back-end logic from the application, and to quickly improve the UI/UX by specializing in application-side user interface development. “As cashless payment systems become more prevalent in society and competing services proliferate, we wanted to strengthen our competitiveness and deliver new, valuable, and easy-to-use applications to our customers even faster. Therefore, we decided to shift to an agile development system as well as large-scale architecting," said Mr. Tetsuo Ohori, Manager in charge of Wallet Services, Product Design Department.

Aiming for enhanced security and NoOps (operation-less)
Utilizing AWS Managed Services

The company decided to carve out the application-side logic as a back-end system and chose AWS as the platform for the migration. The reasons for this were that it was easy to expand to accommodate customer growth, CI/CD support, and the company's high security requirements.

“For one thing, the well managed services and support from AWS allow engineers to focus on building applications. The second was that it already had third-party security certifications for providing financial services and had a full range of security features, including log management, access control, and identity management. In addition, we have been using AWS since 2012, so we have a lot of in-house knowledge. We also liked Amazon's culture of taking care of its customers, the speed at which its services evolve, and its willingness to give back to its customers through continuous price reductions," said Mr. Ohori.

The development of the back-end system will take place in 6 months, from October 2020 to March 2021. After running the old and new systems in parallel, we transitioned to the new service delivery infrastructure from July to September 2021. The architecture is based on serverless operation and containers (e.g., Amazon DynamoDB and AWS Fargate), and a CI/CD environment has been built to automate deployment and reduce costs. To meet different requirements, security functions are implemented using AWS managed services (e.g., AWS WAF and Amazon GuardDuty).

“Our goal was to achieve NoOps (meaning "no operation"). We have actively leveraged managed services in order to focus our development resources on delivering value to our customers. Moreover, by using containers and a serverless architecture that automatically scales based on traffic, we are able to reduce operational overhead and optimize costs while maintaining stable service operations," said Mr. Ohori.

Scrum development to improve functionality once every two weeks
Performance improvement and other measures

By separating the application from the backend, we can estimate the cause of problems based on AWS service usage, logs, etc., and quickly resolve them when they occur. It also reduces functional differences between Android and iOS and issues that are unique to one operating system.

There has also been a dramatic improvement in development productivity. Today, the company has moved to Scrum development with a small number of members with divided roles, and multiple Scrum teams developing applications and systems on AWS in an agile manner. While we add features and improve functionality and UI in two-week sprints, we also respond to sudden development needs and customer suggestions that arise in parallel.

"As a result, we are able to add and enhance dozens of features each year on systems running on AWS alone. Currently, new features and UI enhancements are released on a weekly basis for both the application and the system. When a system release adds functionality, unlike in the past, there is no need for customers to update their applications, and all customers are immediately updated," said Mr. Ohori.

One of the typical actions taken in Scrum development is to improve the performance of the application. When it comes to cashless payments, application responsiveness has a direct impact on payment opportunities and customer satisfaction. Therefore, the speed of the Home screen, payment screen, and so on is constantly being improved by the development team. Delivering services and campaigns linked to points and coupons as needed is one way to improve the customer experience. In June 2022, we revamped our d Point Club points program service and released a service that allows customers to accumulate d points more profitably by using d-Barai.

"We were able to achieve these measures because the reduced operational workload from AWS allowed us to spend more time delivering new value to our customers. As a result, the speed the service evolved greatly improved, contributing to the value of the customer experience. The early release of the product through Scrum development allows us to respond more quickly than ever to the various feedback we receive from our customers, and it has increased the motivation of our engineers," said Mr. Ohori.

NTT DOCOMO will continue to improve the application and back-end, taking advantage of the new environment and structure, while striving to provide easier-to-use, safer and more secure payment services.

"d-Barai has come to play a number of roles as a point of contact for the day-to-day contact with our financial services. We will continue to utilize AWS services as much as possible and improve performance and functionality to achieve a cashless service that is easy to use and can be used by a wider range of customers with peace of mind and satisfaction," said Mr. Ohori.


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