Senior Data Science Engineer / Senior Machine Learning Engineer - Data Insights

**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:** Own end-to-end design, implementation, evaluation, and maintenance of machine learning models for prediction, recommendation, anti-fraud, etc. from problem framing to production Lead architectural decisions for data science systems. Process, analyze, and visualize user and merchant data, providing data-driven insights that influence product strategy for technical and business divisions. Collaborate with data engineers, product managers, and stakeholders to build robust production systems Requirements Bachelors in a quantitative field such as Computer Science, Machine Learning, Mathematics, Statistics, Economics, Physics, or equivalent Verbal and written communication skills in English. English is the primary working language for the team; Japanese is beneficial for cross-functional collaboration. More than five years of work experience as a data scientist, machine learning engineer, or equivalent role Experience in Python and SQL (any variant) Nice to haves While not specifically required, tell us if you have any of the following. Masters or PhD in a quantitative field such as Computer Science, Machine Learning, Mathematics, Statistics, Economics, Physics, or equivalent More than seven years of experience as a data scientist, machine learning engineer, or equivalent role Experience with Big Data technologies like BigQuery, Spark, Hadoop, AWS Redshift, Kafka, or Kinesis streaming Experience with recommendation systems, deep learning, NLP, optimization, or anti-fraud systems Experience with AWS services such as Glue, SageMaker, Athena, and S3 Experience with Databricks or Snowflake Experience designing and conducting A/B and hypothesis tests Experience building and maintaining microservices Verbal and written communication skills in Japanese APPLY FOR THIS POSITION DO YOU NEED MORE INFO? ASK A QUESTION Meet PayPay's Developers Growing your career by asking for you want with Ashwini Meshram Ashwini leads one of PayPay’s payment sub-teams. She got there by doing something she’s done throughout her career: identifying something she wants to do and asking to do it. Read their story... Refactoring PayPay’s Android App with Adrian Mariadas Adrian came to Japan to join PayPay as an Android Engineer. As the app has grown in scope, refactoring the codebase to ensure development can continue at a rapid pace has been a big part of his job. Read their story... iOS Development at PayPay with Yoseph Savianto Yoseph joined PayPay after being attracted to their mission of making Japan a cashless society. As an iOS Engineer, he originally joined their iOS feature team, but now works on their platform team, creating an internal SDK for their iOS and Android apps. Read their story... Rapidly scaling to tens of millions of users with Shilei Long Shilei started working on PayPay before it launched, and has seen it grow into a product used by tens of millions of users. He explains how diversity has helped them overcome challenges, and what PayPay is looking for in candidates. Read their story... **Requirements:** Bachelors in a quantitative field such as Computer Science, Machine Learning, Mathematics, Statistics, Economics, Physics, or equivalent Verbal and written communication skills in English. English is the primary working language for the team; Japanese is beneficial for cross-functional collaboration. More than five years of work experience as a data scientist, machine learning engineer, or equivalent role Experience in Python and SQL (any variant) **Nice to have:** While not specifically required, tell us if you have any of the following. Masters or PhD in a quantitative field such as Computer Science, Machine Learning, Mathematics, Statistics, Economics, Physics, or equivalent More than seven years of experience as a data scientist, machine learning engineer, or equivalent role Experience with Big Data technologies like BigQuery, Spark, Hadoop, AWS Redshift, Kafka, or Kinesis streaming Experience with recommendation systems, deep learning, NLP, optimization, or anti-fraud systems Experience with AWS services such as Glue, SageMaker, Athena, and S3 Experience with Databricks or Snowflake Experience designing and conducting A/B and hypothesis tests Experience building and maintaining microservices Verbal and written communication skills in Japanese APPLY FOR THIS POSITION DO YOU NEED MORE INFO? ASK A QUESTION Meet PayPay's Developers Growing your career by asking for you want with Ashwini Meshram Ashwini leads one of PayPay’s payment sub-teams. She got there by doing something she’s done throughout her career: identifying something she wants to do and asking to do it. Read their story... Refactoring PayPay’s Android App with Adrian Mariadas Adrian came to Japan to join PayPay as an Android Engineer. As the app has grown in scope, refactoring the codebase to ensure development can continue at a rapid pace has been a big part of his job. Read their story... iOS Development at PayPay with Yoseph Savianto Yoseph joined PayPay after being attracted to their mission of making Japan a cashless society. As an iOS Engineer, he originally joined their iOS feature team, but now works on their platform team, creating an internal SDK for their iOS and Android apps. Read their story... Rapidly scaling to tens of millions of users with Shilei Long Shilei started working on PayPay before it launched, and has seen it grow into a product used by tens of millions of users. He explains how diversity has helped them overcome challenges, and what PayPay is looking for in candidates. Read their story...