Full Stack QA Engineer

**About the company:** PayPay Minato-ku, Tokyo With over 70M million registered users (as of July 2025), PayPay is the country’s most popular mobile wallet used by approximately one out of every two smartphone users in Japan. **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 APPLY FOR THIS POSITION DO YOU NEED MORE INFO? ASK A QUESTION About PayPay PayPay Minato-ku, Tokyo With over 70M million registered users (as of July 2025), PayPay is the country’s most popular mobile wallet used by approximately one out of every two smartphone users in Japan. Key benefits International engineering team Incredible scale Read more More jobs like this We'll send you a digest of new English-friendly software developer jobs in Japan. Your email stays private, we don't share or sell it. Apply for this position × I have a favour to ask. When you apply to PayPay, please select "Tokyo Dev" from the Application route field . This helps to keep this job board sustainable, so I'd be grateful for your support with this. - Paul, Founder of TokyoDev Continue applying © 2026 Privacy Policy **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 have:** 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 APPLY FOR THIS POSITION DO YOU NEED MORE INFO? ASK A QUESTION About PayPay PayPay Minato-ku, Tokyo With over 70M million registered users (as of July 2025), PayPay is the country’s most popular mobile wallet used by approximately one out of every two smartphone users in Japan. Key benefits International engineering team Incredible scale Read more More jobs like this We'll send you a digest of new English-friendly software developer jobs in Japan. Your email stays private, we don't share or sell it. Apply for this position × I have a favour to ask. When you apply to PayPay, please select "Tokyo Dev" from the Application route field . This helps to keep this job board sustainable, so I'd be grateful for your support with this. - Paul, Founder of TokyoDev Continue applying © 2026 Privacy Policy