The decision to adopt AWS as a cloud service came after a number of considerations. The key to this decision was their experience in development with Paytm, with whom PayPay was involved in technical collaboration. Yamamoto Keisuke, Head of the Technology 1 Department, Product Division said, "Initially, we were also considering using an on-premises environment. However, because of the time and effort required we decided to focus on the cloud as it is more agile, and thus selected AWS because of its expertise with Paytm."

This decision was also based on a comprehensive assessment of scalability in anticipation of business growth, high availability, and compliance with security measures such as PCI DSS required for payment services. In order to achieve this release in a short period of time, a microservice architecture was employed combining small, highly independent services. The operating platform for the service groups uses Kubernetes, a container management tool deployed on Amazon EC2. The platform comprises more than 60 microservices, each running on independent resources. The microservices are asynchronously linked together using APIs and the Apache Kafka distributed message queue.

Customer identification credentials are securely stored using client-side encryption, server-side encryption, network restrictions, and managed security services. Development comprised a multinational team of engineers formed by linking together three bases in Tokyo, India, and Canada. Rapid development required that each team be responsible for their own areas of expertise, and consider multiple services as they went along.

"We separated the roles of the teams in putting the service together. Core payment and balance management systems were handled by the Canadian team, and the Japanese team handled things like integration with banks and merchant management screens”. (Keisuke)

As planned, the initial launch project was completed in three months, leading to a successful launch of PayPay. Aditya analyzes the factors for the project's success.

"First, the most important thing is to ensure common goals. Second is controlling the core time. Third is overcoming language barriers. We also had a dedicated team of translators and interpreters participate to handle language issues. We understood the cultural differences of each country, and took into account work-life balances. In order to facilitate inter-team communication, we held a weekly meeting at which we shared the status of each team and gave recognition to results."

After the initial launch of PayPay, the company continued to leverage AWS account teams and enterprise support to add new services, and to provide updates to enhance the functionality of each micro-service.

"We requested that the AWS support team be on hand on the day of the campaign, and had them help with scaling. We normally receive advice on architectures as well as information about new AWS services. Because AWS is updated every day, engineers find developing on AWS very rewarding." (Keisuke)

Current infrastructure operations are handled by the SRE team of around 10 members, who respond to requests from the service team. In terms of costs, in-depth analysis is carried out through AWS Cost Explorer which provides visibility into resource usage, and operations incorporate daily optimization. Managed services also contribute to reduced operating costs.
According to Aditya, the flexibility and scalability of AWS will be essential as PayPay grows from a start-up to a unicorn and then a decacorn, and it lets the company focus its development resources on delivering added value.

"We're not competing against other payment services—we're competing against cash itself. Our goal is to provide what cash cannot, and to change society. In this, AWS services are essential."

In order to provide stable services, PayPay is looking forward to using the Osaka region, which became a full region in March 2021. Keisuke says "We'd like to use this for simple backups, but also use an active-active architecture between Tokyo and Osaka to guarantee stability while distributing traffic. We would like AWS help in designing our architecture."

On the business side, they are developing PayPay to be a "super app" rather than just a specialized payment-only service, and by expanding its scope enrich and make people's lives more convenient.

"The goal of PayPay is to be a cashless platform. To achieve this, it is important that it be used by many people. We need to develop PayPay into an app that can support all aspects of payment, such as linking it with ride services and asset management services. In addition, I would like PayPay to be an interface with service companies, in a way that they can provide useful value to users." (Aditya)