Senior Backend Engineer (Principal/Tech Lead)

Remote OK - Anywhere in Japan
Full-time
April 10, 2024

Responsibilities

Design and develop large-scale systems to support high throughput applications with complex requirements.
Utilize infrastructure effectively to address scalability challenges.
Contribute to open source projects and develop tools to improve system efficiency.
Embrace problem-solving as a core practice, focusing on root cause analysis and providing ongoing support for production code.

Tech Stack

Our technology stack may vary based on project needs. Currently, we utilize:

Programming Languages: Java, Kotlin, Scala
Frameworks and Tools: Spring Boot, JUnit, Resilience4j, Feign
Databases: MySQL/AuroraDB, DynamoDB, ELK, Kafka, Redis, TiDB
Deployment and Orchestration: Docker, Kubernetes, ArgoCD, AWS, GCP
Development Tools: GitHub, IntelliJ, Gradle, Maven, npm/yarn, Flyway, Jenkins
Data Analytics: BigQuery, Kibana, Spark
Diagramming Tools: PlantUML, draw.io, miro.com
Communication: Slack, Zoom

Qualifications

Proficiency in Java or equivalent programming languages (Scala, Python, Go).
Eagerness to learn new languages and technologies as required.
Experience with SQL and NoSQL databases, as well as distributed caching.
Strong understanding of data structures, algorithms, and object-oriented programming principles.
Knowledge of concurrency and distributed computing.
Hands-on experience with RESTful APIs, Pub/Sub Systems, and Database Clients.
Familiarity with microservices architecture.
Previous involvement in designing and maintaining high-traffic systems.
Bachelor's degree in Computer Engineering, Computer Science, or equivalent experience in SaaS platform development (minimum 5 years).
Fluent in English or Japanese.

Preferred Qualifications

Previous experience in developing new products from inception.
Ability to design systems compliant with legal and security standards, with strong leadership skills for requirement identification.
Experience in improving system resilience and implementing disaster recovery strategies.
Awareness of market trends and needs, prioritizing speed and quality through MVP approaches.
Track record of delivering products within tight deadlines.
Commitment to continuous product improvement post-launch.
Strong cost-efficiency mindset with effective system cost analysis skills.
Willingness to share experiences and foster a culture of learning and improvement.
Experience in finance, payment, or related industries.
Additional language proficiency in Japanese and English is a plus.
Experience with AWS services.

APPLY NOW ➜

About PayPay

PayPay, a FinTech company that has achieved more than 69M users (as of May 2025) within around six years since its launch in 2018, is rapidly expanding its business scale as a payment platform used by approximately one out of every two smartphone users in Japan.

The company has a diverse team of professionals from more than 50 countries and is building a world-class engineering organization.

PayPay's biggest competitor is "cash". They are seeking people who can accept this challenge positively, brush up on the product at a tremendous speed that other companies could never achieve, and who are passionate about promoting and spreading such a financial life platform in a short time along with professionalism.

Japanese Language Policy
At PayPay, there is a mixture of Japanese and English spoken. Around 80% of their product team’s discussions happen in English, and they have technical interpreters and translators on staff to facilitate any translation necessary. Some members can speak both English and Japanese, but some can only speak either English or Japanese.

PayPay doesn’t have an official shared language, but in practice English tends to be the primary language used for internal communications and technical discussions like code reviews.

Instead of requiring that everyone be able to speak a specific language, PayPay expects an ability to communicate with mutual respect and a drive to ensure that you’re understood. The product team values proactive communication highly.
Visa Sponsorship
PayPay sponsors visas for applicants from overseas.
Paid Leave
- Days Off: Saturdays and Sundays. National holidays. Year-end and New Year holidays.
- Holidays: Annual paid leave, congratulatory or condolence leave, maternity leave and etc.
Benefits
🌎 Translation/interpretation support (EN<>JP)

🧡 Support for translation or other administrative tasks in Japanese

👍 Support from bilingual PIC for engineers

🇯🇵 Free Japanese lessons on company time

💻 PC and phone are given (based on the company’s regulations)

👩‍🎓 Training Program: We have various training programs for different kinds of needs

💜 Social security/insurance benefits included

💛 Defined contribution pension system (TBC)

🏥 Health insurance

🚃 Transportation coverage (up to ¥150,000/mo)
Engineer Interview Process
PayPay's Hiring process are as below:
- Application Review (English CV is required)
- Coding Test or Take Home Assignment (only applied to required positions)
- 3-4 Interviews (including both technical and behavioral interviews)
- Offer Meeting
Remote Work
PayPay is committed to maintaining a "Day 1" mindset, bringing to life visions of the future that no one else can even imagine. At PayPay, we provide an environment where everyone can deliver outstanding performance as professionals, through a flexible work style that includes remote and office.
Work style
- Super Flex Time with no core time
- In principle, from 9:00am-5:45pm (actual working hours: 7h45m + 1h break)