Backend Engineer

Summary

PayPay is a FinTech company that has grown to over 70M users since its launch in 2018. They are looking for a Backend Engineer to work on their payment system, focusing on delivering the best payment experience for customers while leveraging AI tools in their engineering processes.

Responsibilities

• Design large-scale systems with high complexity to support our high throughput applications
• Understand how to leverage infrastructure for solving such large-scale problems
• Develop tools and contribute to open source wherever possible
• Adopt problem solving as a way of life – always go to root cause! Support the code you write in production
• Leverage AI/LLM-based tools for code development, reviews, testing, and documentation in daily workflows

Skills

• 4+ years of experience in using Java under professional environment, or if you are non-Java user, excellent skills in generalized programming languages, such as Scala, Python, and Go
• Interest and ability to learn other coding languages as needed
• Experience with NoSQL databases and 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
• Business level of English or Japanese
• Hands-on experience with AI/LLM tools (e.g., ChatGPT, GitHub Copilot, Gemini, CodeWhisperer, or similar) in professional software development
• Experience with implementing platform components such as RESTful APIs, Pub/Sub Systems, Database clients
• Experience with AWS services
• Experience in working for system development in finance, payment, or similar industries
• Experience in system design, development of web systems which handle massive amount of transactions or require scalability
• Language ability in Japanese and English is a plus (we have a professional translator but it is nice to have language skills)
• Experience in microservices
• Proven track record of integrating AI-assisted development into system design and delivery
• Contributions to AI-related open-source projects or automation of workflows with AI is a plus

Qualifications

Must Haves

• 4+ years of experience in using Java under professional environment, or if you are non-Java user, excellent skills in generalized programming languages, such as Scala, Python, and Go
• Interest and ability to learn other coding languages as needed
• Experience with NoSQL databases and 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
• Business level of English or Japanese
• Hands-on experience with AI/LLM tools (e.g., ChatGPT, GitHub Copilot, Gemini, CodeWhisperer, or similar) in professional software development

Nice to Haves

• Experience with implementing platform components such as RESTful APIs, Pub/Sub Systems, Database clients
• Experience with AWS services
• Experience in working for system development in finance, payment, or similar industries
• Experience in system design, development of web systems which handle massive amount of transactions or require scalability
• Language ability in Japanese and English is a plus (we have a professional translator but it is nice to have language skills)
• Experience in microservices
• Proven track record of integrating AI-assisted development into system design and delivery
• Contributions to AI-related open-source projects or automation of workflows with AI is a plus

Benefits

• VISA sponsor + Relocation support
• Social Insurance (health insurance, employee pension, employment insurance and compensation insurance)
• 401K
• Translation/Interpretation support