DatVietVAC Group Holdings is looking for a Principal/Expert Backend Engineer to build and operate the core backend services of our Fan Commerce Platform.

You will design high-concurrency distributed systems that support major on-sale periods and entertainment events. This role is responsible for ensuring platform scalability, transaction accuracy, data security, local data residency, and reliable delivery across the product roadmap.

1. Backend Platform and High-Concurrency Systems

• Design, develop, and operate scalable core backend services for the Fan Commerce Platform.
• Build systems capable of handling sudden traffic spikes during major on-sales and live events.
• Design shared-resource management mechanisms for inventory and reservations.
• Ensure consistency, idempotency, and reliable conflict handling in distributed environments.
• Design asynchronous processing flows, messaging queues, rate limiting, backpressure, and overload-protection mechanisms.
• Conduct capacity planning and collaborate with SRE Engineers on load and performance testing.
• Identify performance bottlenecks and optimize system throughput, latency, and resource utilization.

2. Commerce and Payment Services

• Develop core commerce services covering product catalogues, inventory, reservations, orders, promotions, and fulfilment-related integrations.
• Integrate payment gateways and implement secure payment workflows.
• Process payment webhooks, refunds, cancellations, and transaction reconciliation.
• Ensure the integrity, accuracy, and traceability of financial and transactional data.
• Design mechanisms to prevent duplicate processing, overselling, inconsistent inventory, and transaction loss.
• Integrate third-party services, including payment, logistics, notification, and partner systems, through reliable APIs and integration contracts.

3. Shared Services and Event-driven Architecture

• Build shared platform services, including authentication, authorization, user profiles, and system configuration.
• Develop event-driven data pipelines for data synchronization, analytics, and service integration.
• Design clean and maintainable REST and gRPC APIs.
• Define API and event contracts between microservices.
• Ensure backward compatibility and enable individual services to scale and evolve independently.
• Design asynchronous workers and reliable event-processing mechanisms.
• Contribute to architectural decisions for distributed systems, databases, caching, and messaging.

4. Data Residency, Security, and Compliance

• Design data architecture that meets local data-residency requirements in Vietnam.
• Support the separation of compute workloads and sensitive data across the relevant infrastructure environments.
• Implement role-based access control, encryption, secrets management, and audit logging for sensitive operations.
• Apply secure coding practices and relevant OWASP principles.
• Collaborate with SRE, Security, and other teams on penetration testing and vulnerability remediation.
• Support requirements relating to personal data protection, security audits, and technical compliance.
• Contribute to anti-fraud, anti-bot, and abuse-prevention mechanisms.

5. Engineering Quality and Technical Leadership

• Build scalable microservices with complete observability across metrics, logs, and traces.
• Write and maintain unit, integration, and load tests for critical services.
• Contribute to CI/CD pipelines and Infrastructure as Code practices.
• Review code and ensure compliance with agreed architecture, coding standards, security requirements, and engineering conventions.
• Make well-reasoned technical decisions and clearly communicate architectural trade-offs.
• Establish engineering standards, reusable patterns, and development guidelines.
• Mentor engineers and provide technical direction within the team.
• Collaborate closely with Product Owners, Frontend and Mobile Engineers, SRE/DevOps Engineers, UX/UI Designers, and QC Engineers.

Education

• Bachelor's degree in information technology, Software Engineering, Computer Science, or a related field.

Experience

• At least five years of professional experience as a Backend Engineer, Software Engineer, or in a similar backend development role.
• Proven experience designing and operating production-grade distributed systems.
• Experience building transactional systems in e-commerce, fintech, payment, ticketing, reservation, or other high-concurrency environments is highly preferred.
• Hands-on experience taking a greenfield product from initial architecture and development to production operations.
• Experience providing technical direction, conducting code reviews, or mentoring engineers.

Technical Knowledge and Skills

• Strong proficiency in Golang for developing production-grade backend services.
• Working knowledge of Python, [protected info], or TypeScript is an advantage.
• Strong understanding of distributed systems, microservices, and event-driven architecture.
• Deep knowledge of database transactions, isolation levels, distributed locking, idempotency, and consistency models.
• Strong experience designing and optimizing PostgreSQL databases at scale, including indexing, partitioning, query optimization, and replication.
• Experience with caching strategies, message queues, asynchronous processing, backpressure, load testing, and capacity planning.
• Hands-on experience with Redis and Kafka, Pub/Sub, or equivalent messaging technologies.
• Experience integrating payment gateways, processing webhooks and refunds, and implementing transaction reconciliation.
• Strong understanding of REST and gRPC API design.
• Experience with Kubernetes, Docker, and production cloud environments.
• Experience with Google Cloud or AWS.
• Understanding of application security, OWASP principles, secrets management, RBAC, audit logging, and personal data protection.
• Experience with CI/CD, Infrastructure as Code, and observability tools.

Tech Stack

• Languages: Golang, Python, [protected info], TypeScript
• Frameworks and APIs: gRPC, REST, FastAPI, NestJS, Express
• Databases: PostgreSQL, MongoDB
• Messaging and caching: Kafka, Pub/Sub, Redis
• Infrastructure: Kubernetes, GKE, Docker
• Cloud and security: Google Cloud, AWS, Cloudflare
• Tooling: GitHub Actions, Terraform, Prometheus, Grafana, Datadog

Soft Skills

• Strong analytical thinking and structured problem-solving skills.
• Ability to make technical decisions based on data, system requirements, and clearly understood trade-offs.
• Strong ownership and the ability to work effectively under fixed release deadlines.
• Ability to communicate complex technical decisions to both technical and non-technical stakeholders.
• Strong collaboration skills when working with Product, Frontend, Mobile, SRE/DevOps, and QC teams.
• Ability to provide technical leadership and mentor engineers within a small team.
• High attention to detail, particularly when working with transactional and financial data.

Language Skills

• Basic English communication skills.
• Good ability to read and understand technical documentation in English.

• Full statutory insurance, including Social Insurance, Health Insurance and Unemployment Insurance, based on 100% of the official salary and in compliance with Vietnamese labor regulations.
• Working hours: Monday to Friday, from 8:30 AM to 5:30 PM, with a one-hour lunch break.
• 14 days of annual leave.
• Company-provided working equipment, including a laptop or desktop computer.
• Employee parking area.
• Annual PMP performance bonus, subject to individual KPI achievement and the Company's business performance.
• Periodic health check-ups.
• Employee engagement programs and internal activities throughout the year.