Backend Engineer
About PayPay Card
PayPay Card Corporation was established in 2021 to provide users a FinTech service that is more accessible and convenient compared to previous credit cards and credit services, by integrating with the PayPay payment platform, which has surpassed 70 million users since its launch (as of July 2025).
We are looking for people who are passionate about refining our products at an overwhelming speed that other companies cannot match, as well as professionals who are interested in promoting the spread of cashless payments in Japan and the use of these payments as a financial life platform. Let us work together to create new value for users.
※ Please note that you cannot apply or be selected in parallel with PayPay Corporation, PayPay Card Corporation and PayPay Securities Corporation.
Job Description
We are looking for backend engineers to build, or rebuild, rock solid services with a laser focus on scalability and maintainability.
PayPay Card aims at revolutionizing the credit card industry, making payment easier than ever, from two different angles:
- Bring the credit card experience to the next level: we have many functionalities in the pipe to improve our product, not to mention the integration into the PayPay ecosystem as PayPay Card is part of the PayPay Group.
- (Re-)architect our systems landscape: we want to reassess and fix the behind-the-scenes to power a top-notch user experience. It is bundled with difficult design challenges to solve: we simply want to get it right.
As a fast-paced company leading the payments industry, we need our engineers to be versatile and enthusiastic to take on new challenges in order to stay at the forefront. Indeed, we strive for continuous improvement within our systems as well as outside our systems. Additionally, we value communication, to smoothly cooperate with other teams, and inclusivity, to efficiently navigate in a multicultural environment.
Main Responsibilities
- Support the design, implementation and delivery of large scale, and complex, systems, while collaborating with product managers, frontend engineers or other team members.
- Understand how to leverage infrastructure to solve large scale problems.
- Contribute to the team by sharing knowledge, participating in code reviews and providing feedback to uphold and ensure best practices.
- Triage, debug and resolve product issues or other incoming troubles inquiries
- Adopt problem solving as a way of life – always go to the root cause! Support the code you write in production.
Tech Stack
We currently work with
- Back-end services:
- Main implementations are in Spring Boot, with a mix of Java 11/Spring Boot 2 and Java 17/Spring Boot 3.
- Some legacy systems are written in Java EE.
- Testing is done with JUnit and Mockito
- Deployment relies on AWS ECS
- CI/CD is handled by AWS CodePipeline
- Infrastructure
- All our services run in AWS
- Infrastructure is managed by AWS CloudFormation
- AWS CloudWatch is used for observability
- Coding environment: GitHub, IntelliJ, Gradle
- Documentation & Project management: Confluence, Miro, JIRA
- Communication: Slack, Zoom, Office 365
Please note that PayPay Card is challenging its current architecture, potentially introducing new technologies and/or deprecating existing ones.
Required Qualifications
- Skills in OOP language such as C# or other JVM language, such as Scala are welcome
- Experience with RDBMS, NoSQL databases along with distributed cache.
- Strong fundamentals in data structures, algorithms and object oriented programming.
- In-depth understanding of concurrency and distributed computing.
- Experience implementing platform components such as RESTful APIs, Pub/Sub Systems, and Database Clients.
- Experience with microservices and event-driven architectures.
- Experience designing high traffic systems.
- Degree in Computer Engineering or Computer Science or 3+ years equivalent experience in SaaS platform development.
- English business proficiency
Preferred Qualifications
- Domain-driven development knowledge
- Java/Spring Boot experience
- gRPC and Kafka development experience
- Experience in a multicultural environment
- Stakeholder management is welcomed
- Japanese conversational proficiency is a plus
Working Conditions
Employment Status
- Full Time
Office Location
- Hybrid Workstyle (flexible working style including Remote and office)
※There are no fixed rules regarding office attendance in Technology group; it depends on each individual's discretion.
Work Hours
- Full Flex Time (No Core Time)
- In principle, 9:00am ~ 5:45pm (actual working hours: 7h45m + 1h break)
Holidays
- Every Sat/Sun/National holidays (In Japan)/New Year's break/Company-designated Special days
Paid leave
- Annual leave (up to 14 days in the first year, granted proportionally according to the month of employment. Can be used from the date of hire)
- Personal leave (5 days each year, granted proportionally according to the month of employment)
＊PayPay Group's own special paid leave system, which can be used to attend to illnesses, injuries, hospital visits, etc., of the employee, family members, pets, etc.
Salary
- Annual salary paid in 12 installments (monthly)
- Reviewed once a year
- Special Incentive once a year *Based on company performance and individual contribution and evaluation
- Overtime allowance, Late overtime allowance, Commuting and transportation expenses
Benefits
- Social Insurance (health insurance, employee pension, employment insurance and compensation insurance)
- 401K