Backend Engineer

About PayPay Card PayPay Card Corporation was established in 2021 to provide users a FinTech service that is more accessible and convenient compared to previous credit cards and credit services, by integrating with the PayPay payment platform, which has surpassed 69 million users since its launch (as of May 2025). We are looking for people who are passionate about refining our products at an overwhelming speed that other companies cannot match, as well as professionals who are interested in promoting the spread of cashless payments in Japan and the use of these payments as a financial life platform. Let us work together to create new value for users. ※ Please note that you cannot apply or be selected in parallel with PayPay Corporation, PayPay Card Corporation and PayPay Securities Corporation.

Job Description We are looking for backend engineers to build, or rebuild, rock solid services with a laser focus on scalability and maintainability. PayPay Card aims at revolutionizing the credit card industry, making payment easier than ever, from two different angles:

Bring the credit card experience to the next level: we have many functionalities in the pipe to improve our product, not to mention the integration into the PayPay ecosystem as PayPay Card is part of the PayPay Group.

(Re-)architect our systems landscape: we want to reassess and fix the behind-the-scenes to power a top-notch user experience. It is bundled with difficult design challenges to solve: we simply want to get it right.

As a fast-paced company leading the payments industry, we need our engineers to be versatile and enthusiastic to take on new challenges in order to stay at the forefront. Indeed, we strive for continuous improvement within our systems as well as outside our systems. Additionally, we value communication, to smoothly cooperate with other teams, and inclusivity, to efficiently navigate in a multicultural environment.

Main Responsibilities

Support the design, implementation and delivery of large scale, and complex, systems, while collaborating with product managers, frontend engineers or other team members.

Understand how to leverage infrastructure to solve large scale problems. Contribute to the team by sharing knowledge, participating in code reviews and providing

feedback to uphold and ensure best practices. Triage, debug and resolve product issues or other incoming troubles inquiries Adopt problem solving as a way of life – always go to the root cause! Support the code you write

in production.

Tech Stack

We currently work with Back-end services:

Main implementations are in Spring Boot, with a mix of Java 11/Spring Boot 2 and Java 17/Spring Boot 3.

Some legacy systems are written in Java EE. Testing is done with JUnit and Mockito Deployment relies on AWS ECS CI/CD is handled by AWS CodePipeline

Infrastructure All our services run in AWS Infrastructure is managed by AWS CloudFormation AWS CloudWatch is used for observability

Coding environment: GitHub, IntelliJ, Gradle Documentation & Project management: Confluence, Miro, JIRA Communication: Slack, Zoom, Office 365

Please note that PayPay Card is challenging its current architecture, potentially introducing new technologies and/or deprecating existing ones.

Required Qualifications

Skills in OOP language such as C# or other JVM language, such as Scala are welcome Experience with RDBMS, NoSQL databases along with distributed cache. Strong fundamentals in data structures, algorithms and object oriented programming. In-depth understanding of concurrency and distributed computing. Experience implementing platform components such as RESTful APIs, Pub/Sub Systems, and

Database Clients. Experience with microservices and event-driven architectures. Experience designing high traffic systems. Degree in Computer Engineering or Computer Science or 3+ years equivalent experience in

SaaS platform development. English business proficiency

Preferred Qualifications

Domain-driven development knowledge Java/Spring Boot experience gRPC and Kafka development experience Experience in a multicultural environment Stakeholder management is welcomed Japanese conversational proficiency is a plus

Working Conditions

Employment Status

Full Time

Office Location

Hybrid Workstyle (flexible working style including Remote and office) ※There are no fixed rules regarding office attendance in Technology group; it depends on each individual's discretion.

Work Hours

Full Flex Time (No Core Time) In principle, 9:00am ~ 5:45pm (actual working hours: 7h45m + 1h break)

Holidays

Every Sat/Sun/National holidays (In Japan)/New Year's break/Company-designated Special days

Paid leave

Annual leave (up to 14 days in the first year, granted proportionally according to the month of employment. Can be used from the date of hire)

Personal leave (5 days each year, granted proportionally according to the month of employment) ＊PayPay Group's own special paid leave system, which can be used to attend to illnesses, injuries, hospital visits, etc., of the employee, family members, pets, etc.

Salary

Annual salary paid in 12 installments (monthly) Reviewed once a year Special Incentive once a year *Based on company performance and individual contribution and

evaluation Overtime allowance,Late overtime allowance,Commuting and transportation expenses, Work

style support allowance

Benefits

Social Insurance (health insurance, employee pension, employment insurance and compensation insurance)

401K

Frontend Engineer

About PayPay Card PayPay Card Corporation was established in 2021 to provide users a FinTech service that is more accessible and convenient compared to previous credit cards and credit services, by integrating with the PayPay payment platform, which has surpassed 69 million users since its launch (as of May 2025).

We are looking for people who are passionate about refining our products at an overwhelming speed that other companies cannot match, as well as professionals who are interested in promoting the spread of cashless payments in Japan and the use of these payments as a financial life platform. Let us work together to create new value for users. ※ Please note that you cannot apply or be selected in parallel with PayPay Corporation, PayPay Card Corporation and PayPay Securities Corporation.

Job Description We are looking for web frontend engineers to work on the PayPay Card mini-application, and other web frontend, with a laser focus on scalability and maintainability. PayPay Card aims at revolutionizing the credit card industry, making payment easier than ever, from two different angles:

Bring the credit card experience to the next level: we have many functionalities in the pipe to

improve our product, not to mention the integration into the PayPay ecosystem as PayPay Card is part of the PayPay Group.

(Re-)architect our systems landscape: we want to reassess our frontend systems relevancy and update the architecture according to our product & technical roadmap. It is bundled with difficult design challenges to solve: we simply want to get it right.

As a fast-paced company leading the payments industry, we need our engineers to be versatile and enthusiastic to take on new challenges in order to stay at the forefront. Indeed, we strive for continuous improvement within our systems as well as outside our systems. Additionally, we value communication, to smoothly cooperate with other teams, and inclusivity, to efficiently navigate in a multicultural environment.

Responsibilities

Work with Product Managers, Designers and various tech teams to implement features. Contribute to the team by sharing knowledge, participating in code reviews, and providing

feedback to uphold and ensure best practices. Support architecture improvements Triage, debug, and resolve product issues.

Tech Stack

We currently work with Frontend web application:

Main implementation is in Nuxt 3 (Vue.js 3, TypeScript) Storybook is used for component visualization and UI testing Form validation is handled by Vee-validate Google Analytics is used for product reporting Web application are deployed on AWS ECS, in a Docker container

Coding environment: GitHub, Visual Code Documentation & Project management: Confluence, Miro, JIRA Communication: Slack, Zoom, Office 365

Please note that PayPay Card is challenging its current architecture, potentially introducing new technologies and/or deprecating existing ones. Required Qualifications

At least 3 years of industry experience developing secure web frontend applications in JavaScript and/or TypeScript.

At least 1 year of industry experience with VueJS (preferred), or React. Software engineering best practices and computer science knowledge. English business proficiency

Preferred Qualifications

Experience with frontend performance monitoring and optimization. Experience with designing server side RESTful APIs. Experience with web hosting infrastructure such as CDNs. Knowledge in web components and/or island architecture. Experience in a multicultural environment Japanese conversational proficiency is a plus

Working Conditions

Employment Status

Full Time

Office Location

Tokyo Office You can live anywhere in Japan

Work Hours

Full Flex Time (No Core Time) In principle, 9:00am ~ 5:45pm (actual working hours: 7h45m + 1h break)

Holidays

Every Sat/Sun/National holidays (In Japan)/New Year's break/Company-designated Special days

Paid leave

Annual leave (up to 14 days in the first year, granted proportionally according to the month of employment. Can be used from the date of hire)

Personal leave (5 days each year, granted proportionally according to the month of employment) ＊PayPay Group's own special paid leave system, which can be used to attend to illnesses, injuries, hospital visits, etc., of the employee, family members, pets, etc.

Salary

Annual salary paid in 12 installments (monthly) Reviewed once a year Special Incentive once a year *Based on company performance and individual contribution and

evaluation Overtime allowance, Late overtime allowance, Commuting and transportation expenses, Work

style support allowance

Benefits

Social Insurance (health insurance, employee pension, employment insurance and compensation insurance)

401K

バックエンドエンジニア

開発環境

• 開発言語： Java(Go、 Python、JavaScript 尚可)

• データベース： MySQL

• フレームワーク：SpringCloud

• 開発ツール： idea, vscode, docker, kubernetes など

• ミドルウェア： redis, zookeeper, pulsar, kafka, redshift, netty など

• OS： Linux, MacOS

• インフラ：AWS

主な業務内容

• 暗号資産取引所のシステムの設計・開発・運用

応募資格（必須）

• Web アプリケーション開発経験２年以上 （言語：Java）

• UNIX / Linux 環境での開発経験

• Git を利用したチーム開発の経験

• コンピュータサイエンスの基礎知識（アルゴリズム、データ構造、データベー

ス、ネットワーク等）

• RDMS を利用した開発経験

• コミュニケーションスキル ( 日本語 OR 中国語）

歓迎

• アジャイル/スクラム開発の経験

• Docker / kubernetes を用いた開発・運用経験

• API の設計・開発・運用経験

• 金融システムに関する開発経験

• ブロックチェーン関連の知識

• Web セキュリティの知識

• サーバパフォーマンスの高速化・最適化に関する知識・経験

• AWS, GCP などのクラウドインフラ設計・構築経験

求める人物像

• とにかくプログラミングが好きな方

• 常に新しい技術や OSS の動向を探りながら、長期的視野に立ってソフトウエア

を設計・開発・運用ができる方

• チームワークを重視し、他メンバーを活かす働き方ができる方

• 裁量権のある環境で開発をどんどん進めていきたい方

仕事の魅力

• ブロックチェーンを利用した技術の設計・開発に携われる

• 自ら改善点を考え、改善していく機会が得られる

• システム全般を触ることで、様々な技術や知識を習得できる

雇用形態

正社員（試用期間 原則として３ヶ月）

給与

年俸制（応相談）

※現年収以上の額を提示させていただきます。

※みなし残業時間を含む：45 時間（ 45 時間を超える場合は、その差額を時間外勤

務手当として別途支給する）

勤務時間

9：30～18：30（実働時間 8 時間/休憩 1 時間）

待遇

• 社保完備（健康保険・厚生年金・雇用保険・労災保険）

• 慶弔見舞金

• フリードリンク

• 夜食

• 定期健康診断

休日・休暇

• 年間 120 日

• 土日祝日、年末年始

• 有給休暇

• シックリーブ（体調不良時に使う休暇）

• その他（慶弔休暇、産休、育児休暇など）

アクセス

銀座線 「虎ノ門」駅 徒歩 1 分

日比谷線 「虎ノ門ヒルズ駅」 徒歩 2 分

JR 「新橋」駅 徒歩 12 分

企業情報

▪事業内容

同社は世界有数の暗号資産取引所を運営している OK Group(欧科)の日本法人で

す。2020 年 3 月に日本国内の暗号資産交換業者として金融庁に登録されたことを

受け、同年 8 月にサービスを開始しました。現在主な事業は暗号資産取引所の運

営ですが、将来的にはブロックチェーンに関連する各種サービスも展開していき

ます。具体的には通貨ペアの拡大、新規事業の創出等を予定しています。

▪特徴

• 安定な経営基盤

OK Group は 2013 年創設以来、ブロックチェーン技術の開発とビジネス化に取り

組んでおり、現在では世界各国に拠点を拡大し、3000 人以上の従業員を持つグロ

ーバルグループです。

• エンジニアドリブン

グループ創業者がエンジニア出身ということもあり、弊社におけるシステム開発

部やシステム運用部は重要な部署の１つであり、常に最新の技術を導入できるよ

うに取り組んでいます。

• 柔軟な働き方

スタートアップカルチャーを大切にしています。「サービスや、やるべき業務は組

織の枠にとらわれずにやりたい人がやる」といった社風であり、チャレンジでき

る環境は整っています。既存組織の枠組みに囚われず、必要な事や課題があれば、

主体的に取り組んでいくことが可能です。