Core Engineering - Java Developer

The PayPay Core Engineering team is seeking Java developers to improve their suite of internal libraries. The team focuses on addressing core technical problems, leading the improvement of development practices at PayPay, and supporting development teams through a suite of internal libraries streamlining technical functions such as database queries, queue management, logging, monitoring, and encryption. The ideal candidate will have a background in Java/Kotlin product development, a good understanding of interactions between the application and the infrastructure, and a strong knowledge of inner workings of Java and database management systems. Primary responsibilities include maintaining and implementing new core libraries used by the product development teams, investigating complex performance issues, and actively participating in improving Java/Kotlin development practices in PayPay.

• Maintaining and implementing new core libraries used by the product development teams - this imposes high requirements on the code quality, test coverage, well designed architecture and everything required to produce high quality libraries
• Investigating complex performance issues
• Active participation in improving Java/Kotlin development practices in PayPay - identifying root causes of inefficiencies and technical defects in product development, proposing potential solutions and driving them to the end
• Constant technical improvement and research of the new technologies and best practices
• Assist product development teams in the adoption and updates of internal libraries
• Assist development and infrastructure teams in investigating root causes of complex technical issues

• 3+ years of product development in Java/Kotlin; 6+ years of total development experience
• Experience working with Kafka, MySQL, ElasticSearch or similar technologies
• Experience developing and maintaining high-load high-availability scalable systems
• Experience in application and database performance optimization
• Working knowledge of Gradle and developing Gradle plugins (preferred)
• Experience with TiDB (preferred)
• Experience implementing and maintaining technical libraries (preferred)