Backend Engineer, Credit Review and Receivables Systems

This backend engineering position builds and runs the credit-review and receivables systems behind PayPay Card's credit card business. The Corporate Engineering group develops business systems across the review and receivables, customer and authorization areas, and engineers handle planning, design, development and operation themselves. The company is strengthening in-house development as membership grows and the demands on credit-review and receivables systems rise.

Responsibilities include designing, developing and operating the core systems for credit review, credit limits and receivables management; building the data-integration platform and usage-history retrieval with external credit bureaus; and implementing risk-management logic such as scoring-based credit setting, fraud detection and anti-money-laundering controls. The engineer also develops high-accuracy review functions on real-time, large-scale data processing and functions such as customer search and collection-target extraction that make receivables work more efficient. System design must combine strong security with stable transaction processing. Past projects include optimizing the credit scoring algorithm, bringing ongoing-credit systems in-house, moving paper-form workflows to the web, and renewing the phone platform.

The backend stack covers Java, Kotlin, TypeScript and Python with Spring Boot and MyBatis, GitHub, JUnit, VSCode and Docker, running on AWS (ECS, ECR and other services). BigQuery and Looker Studio are used for data analysis, and Vue.js on the front end.

Applicants need experience developing web applications and APIs in Java, Kotlin or Go; experience building business systems on an RDBMS with a solid grasp of transaction processing; experience designing and implementing RESTful APIs and gRPC; and experience in team development with Git. Experience in finance, credit or payments systems, deep knowledge of Java frameworks such as Spring Boot, optimization of high-traffic or batch processing, cloud development and operations on AWS or GCP, experience as a team or tech lead, end-to-end involvement from basic design to operations, and practical use of generative AI for design, coding, test generation and documentation are welcomed.

The role is full-time and hybrid, working from an office in Tokyo or Fukuoka or remotely from home, with office or remote work depending on the organization's rules and work instructions.

Working conditions: The role is listed with a hybrid location.