Full Stack QA Engineer

Background of Recruitment

We are looking for Full Stack QA Engineer to drive the continued growth of the PayPay Group by continuously improving our banking systems and building a robust, flexible next-generation technology platform.

For New Bank Project, we are redefining finance and building a new banking platform through two key initiatives.

Redefining the Financial Experience

The PayPay Group is building a digital financial platform where users can seamlessly access to every aspect of their financial lives—from earning, growing, protecting, and saving money—all within a single app. As the banking foundation of the PayPay ecosystem, PayPay Bank plays a critical role in enabling every financial service across the platform. By continuously evolving our banking capabilities, we are creating entirely new financial experiences that go beyond the boundaries of traditional banking. Our ambition is not simply to operate a bank—we are challenging ourselves to redefine what finance can be.

Building an In-House Core Banking System

Today’s banking systems demand greater agility, faster development cycles, higher quality, and better cost efficiency. To meet these challenges, PayPay Bank is building a next-generation core banking system entirely in-house, embracing the same global engineering culture that powers PayPay. This is an unique opportunity to contribute to one of the largest core banking modernization projects in the financial industry. You’ll help design and build the technology platform that supports one of Japan’s largest digital user bases while shaping the future of banking from the ground up.

To drive transformation at PayPay’s exceptional speed, we are looking for engineers who are adaptable, proactive, and eager to take ownership beyond defined roles and responsibilities. We value people who create opportunities for themselves, embrace challenges, and turn ideas into impact. Rather than being attached to a particular programming language or technology, we view technology as a means to solve meaningful problems. You will collaborate with your team to maximize product impact and business value, always putting the user first. If you’re passionate about building products with a user-first mindset and helping redefine the future of finance, this is an opportunity for you.

※ After joining the company, you are expected to be seconded to PayPay Bank as a member of the above project.

Team Missions

Serving as an autonomous QA organization in Product Group

• To improve the overall quality of PayPay products and services
• To develop PayPay quality standards and best practices
• To gain trust in quality from PayPay Users and Merchants

Attractiveness of This Position

• Gain experience from the design to the introduction of a new system renewal
• Opportunity to collaboratively build a new organization and environment
• Acquire high-level planning and proposal capabilities through supporting top management’s decision-making and high-level coordination with various departments and affiliated companies, including PayPay
• Gain frontline work experience in the industry at a company aiming to provide unprecedented financial services during a transformative period in the financial industry
• Ability to leverage PayPay’s service and user base

Project Examples

• Application development for new services and improvements to existing services:
• Account opening linked with LINE, inquiry chat
• PayPay mini-app integration
• Expansion of cardless ATM usage
• Improvement of account opening processes
• Improvement of various loan services, etc.

Responsibilities

• Analyze testing requirements to develop comprehensive test scenarios for various test levels
• Design and create detailed test cases that validate conformance to functional and non-functional requirements
• Prepare and manage essential test data, tools, and environments for test execution
• Execute test cases and scripts, meticulously documenting results
• Drive quality improvement with a strong focus on test automation, while also taking ownership of comprehensive validation activities that include manual testing
• Log, track, and verify defects, ensuring accurate documentation and timely resolution
• Collect, organize, and analyze test results to provide thorough reports on all QA activities
• Analyze testing outcomes and recommend effective solutions for identified issues
• Maintain and update comprehensive test documentation, ensuring coverage for new features and robust regression testing
• Support knowledge management and foster collaboration by actively participating in testing discussions and contributing to continuous improvement through lessons learned
• Act as a Subject Matter Expert (SME) for designated modules, providing critical domain knowledge and support to the QA team
• Provide guidance and support to junior QA engineers, including onboarding and training
• Leverage AI tools such as NotebookLM, Gemini, Cursor AI, GitHub Copilot, and OpenAI APIs to accelerate test case design, automation, and exploratory testing
• Apply prompt engineering and RAG (Retrieval-Augmented Generation) techniques to validate LLM-driven applications, ensuring accuracy, reliability, and robustness
• Work with OpenAI keys, LLM models, and MCP server integrations, automating API-based interactions and securing AI workflows
• Test and monitor AI/ML systems for issues such as bias, drift, hallucinations, and performance deviations

Requirements

• Minimum 3+ years of experience in developing, executing, and maintaining automated test cases for mobile applications, web applications, and/or APIs
• Proven professional experience with at least one of the following automation frameworks/tools: Appium (for mobile), Playwright/Selenium (for web), or Rest-Assured (for APIs)
• Proficient in utilizing Cucumber for defining and executing test cases
• Well-versed in Continuous Integration/Continuous Deployment (CI/CD) tools such as Github actions, Bitrise, or similar platforms
• Basic understanding of microservices architecture and its associated testing challenges
• Strong ability to analyze technical requirements, design comprehensive test strategies, and create detailed, effective test cases
• Exceptional analytical and problem-solving skills, coupled with a meticulous attention to detail
• Excellent communication skills, a team-oriented mindset, and the ability to work effectively both independently and collaboratively
• Hands-on experience with AI productivity tools (NotebookLM, Gemini, Cursor AI, GitHub Copilot)
• Knowledge of OpenAI API usage, key management, embeddings, and LLM integration workflows
• Familiarity with MCP server concepts and their integration in test automation pipelines
• Understanding of AI system validation techniques, including testing for bias, hallucinations, drift, and robustness
• Business level of English

Nice to haves

While not specifically required, tell us if you have any of the following.

• ISTQB or an equivalent QA certification
• Experience working in Agile or other fast-paced development environments
• Familiarity with the financial or payments domain is highly desirable
• Experience in proposing and standardizing QA processes, with a proven ability to collaborate effectively with cross-functional teams
• Experience in designing and executing performance tests using tools such as Gatling, wrk, or JMeter
• Familiarity with Docker and Kubernetes for containerization and orchestration
• Experience with bash or other command-line interface (CLI) scripting
• Coding experience in building web or mobile-based applications
• A strong sense of curiosity and a passion for continuously learning new technologies are definite plusses
• Ability to conduct business in Japanese (native-level proficiency or equivalent to JLPT N1/N2)
• 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