Responsible for developing and maintaining back-end services for the Core Identity Services (CIS) using Node.js. CIS acts as the single source of truth for customer identity across multiple independent services. This role supports the CIS team by building secure APIs, handling identity and business logic, and integrating with databases and external services, working closely with the other developers on the project to deliver reliable and scalable back-end features.

1. Back-end Development
 Develop, maintain, and enhance CIS back-end services and REST APIs on Cloud Run using Node.js (persons, consent, service-data, privacy, service-registry endpoints).
 Implement API behaviour per the service contract — request validation, idempotency, optimistic concurrency (versioning), pagination, field-level ACLs, and structured (RFC 9457) error responses.
 Implement service-to-service authentication and authorization (Google OIDC ID tokens, service JWTs, scopes) and enforce field ownership rules.
 Ensure services are secure, well-structured, testable, and maintainable.

2. Integration, Events & Background Jobs
 Build and maintain integrations with source systems and third-party platforms (Shopify webhooks/GraphQL, Klaviyo REST), including HMAC signature verification. Implement and support event-driven flows using Pub/Sub — publishing observations, consuming events, and handling at-least-once delivery and idempotency.
 Support webhook fan-out (signing, retries, dead-lettering) and the reverse-ETL / sync jobs that move data between the Data Lake, PostgreSQL, and Klaviyo.

Quality & Maintenance
 Debug, fix bugs, and improve the stability and performance of back-end services.
 Write clean, maintainable, and well-documented code following coding standards and best practices.
 Participate in code reviews and contribute to improving code quality and processes.
 Assist with deployment, monitoring, and basic operational support of back-end services.

3. Collaboration
 Work closely with the Core Identity Services team members to support and deliver features end to end.
 Participate in technical discussions, estimation, and planning.
 Communicate progress, blockers, and risks clearly with the team.
Skills & Qualifications
4. Must-have
 Bachelor's degree in Computer Science, Software Engineering, or a related field.
 Experience developing back-end services with Node.js (Express, NestJS, or equivalent frameworks).
 Solid knowledge of JavaScript/TypeScript and asynchronous programming.
 Experience designing and building RESTful APIs.
 Working knowledge of relational databases and SQL; ability to write and optimize queries.
 Understanding of authentication and authorization concepts (sessions, tokens/JWT, hashing) and basic API security practices.
 Experience with Git and collaborative development workflows.
 Careful, responsible, and willing to learn and collaborate with the team.
 Ability to read and understand technical documentation English.Nice-to-have
 Experience with identity/authentication flows or libraries (OAuth2, OpenID Connect, JWT, Passport, or equivalent).
 Experience with NoSQL databases (MongoDB, Redis, or equivalent).
 Experience with data integration, ETL, or working with large or consolidated datasets.
 Experience with message queues, caching, or background job processing.
 Experience with cloud services (AWS, GCP, or Azure) and containerization (Docker).
 Experience with automated testing and CI/CD workflows.
 Experience working in a software company, outsourcing company, or an environment with multiple client projects.
 Interest in or experience with the sports/golf industry is a plus.

Trong tuần: Từ thứ 2 - thứ 6

Trong ngày: Từ 08:30 giờ - 17:30 giờ

Opportunities to onsite and work with big customers, advanced technology, personal development...
- Opportunity to work in groups with many leading experts in the field of domestic and international IT.
- Opportunity to implement ambitious projects in many countries, gain exposure to the latest technologies and learn from talented colleagues.
- Work in a youthful, vibrant, modern and multicultural environment. Communication activities and events on holidays take place regularly.
- Promotion opportunities based on capacity with corresponding rank increases and salary increases.
- Have the right to participate in soft skills training courses (logical thinking, creative thinking, communication skills, project management skills, negotiation skills...) and Japanese language classes.
- And many other attractive benefits...

Onsite Dương Đình Nghệ, HN