Senior 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 senior 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 Design, support the implementation and deliver large scale, and complex, systems Manage teams stakeholders such as product managers or frontend engineers but also other team leads or non-tech stakeholders. Leverage the infrastructure to solve such large scale problems. Acts as a gatekeeper to the team quality standard Triage, debug and resolve product issues or other incoming inquiries Mentor other team members and saveguard the team quality standards 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 Experience in any OOP based language e.g Kotlin, Java, C#, Scala etc. Experience with RDBMS and NoSQL databases, along with distributed cache. Strong fundamentals in data structures, algorithms and object oriented programming. In-depth understanding of concurrency and distributed computing. Degree in Computer Engineering or Computer Science or 5+ years equivalent experience in SaaS platform development. English business proficiency Preferred Qualifications Experience with Java/Spring Boot framework Experience with implementing platform components such as RESTful APIs, Pub/Sub Systems, Database Clients. Experience in system design for high traffic application with scalability in mind Experience with microservices & event-driven architecture Experience gRPC communication design and implementation Experience in a multicultural environment Japanese conversational proficiency is a plus Working Conditions Employment Status Full Time Office Location Hybrid Workstyle (flexible working style including Remote and office) ※ You will be expected to work both in the office and remotely, in alignment with organizational guidelines and team objectives. LIFE in JAPAN FACTBOOK 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 Overtime allowance, Late overtime allowance, Commuting and transportation expenses Benefits Social Insurance (health insurance, employee pension, employment insurance and compensation insurance) 401K Other Information PayPay Inside-Out (Corporate Blog) JP ENG Recruiting FACTBOOK for PayPay Card JP