Senior Node.js Backend Developer

Hi! We are looking for a Senior Node.js Backend Developer (Payments Platform) to join our pack at SharksCode 🦈💙
SharksCode is a Ukrainian IT company that develops high-tech software solutions and scalable B2B platforms.
We are looking for a Senior Node.js Backend Developer who will help build and evolve our payment platform, working on scalable backend services, distributed systems, and integrations with external financial providers. In this role, you will participate in architectural decisions, develop secure and reliable payment flows, and contribute to building resilient, high-load backend services.

We expect that you:
Have 6+ years of commercial backend development experience with Node.js.
Have strong commercial experience with TypeScript and a deep understanding of its type system.
Have hands-on experience designing and developing REST APIs.
Write clean, maintainable, well-tested, and production-ready code.
Have experience decomposing complex business requirements into scalable technical solutions.
Can clearly explain and justify technical decisions, trade-offs, risks, and alternative approaches.
Have strong practical experience with PostgreSQL, including query optimization, indexing, schema design, and performance tuning under high load.
Have hands-on experience designing and developing microservice-based distributed systems.
Understand distributed and event-driven architectures.
Have practical experience working with Kafka.
Have hands-on experience using Redis.
Have experience implementing retries, timeouts, circuit breakers, rate limiting, and backpressure mechanisms.
Have experience integrating third-party APIs, including payment providers, PSPs, banks, KYC providers, or other external services.
Have a solid understanding of secure software development principles.
Have practical knowledge of OAuth 2.0, JWT, HMAC, mTLS, API authentication, and authorization.
Can identify security vulnerabilities in code, APIs, dependencies, configurations, and system architecture.
Have experience conducting code reviews and technical audits of backend services.
Understand principles of protecting personal, payment, and other sensitive data.
Have a strong understanding of HTTP/HTTPS, TCP/IP, DNS, Webhooks, and the lifecycle of network requests.
Understand TLS/mTLS, certificate lifecycle management, rotation, and secure certificate storage.

Your future responsibilities:
Design, develop, and maintain backend services for the payment platform.
Build reliable integrations with payment providers, banks, and external financial services.
Develop scalable microservices and distributed backend components.
Participate in architecture discussions and contribute to technical decision-making.
Optimize PostgreSQL performance and ensure system reliability under high load.
Ensure backend security and compliance with engineering best practices.
Conduct code reviews and contribute to improving engineering standards within the team.
Collaborate closely with product, QA, and infrastructure teams to deliver reliable production solutions.

Nice to have:
Experience with GraphQL or gRPC.
Experience building payment platforms, financial services, or payment processing systems.
Experience in iGaming, Betting, FinTech, Banking, or E-commerce domains.
Understanding of payment lifecycle concepts such as authorization, capture, void, refund, reversal, and chargeback.
Understanding of reconciliation, settlement, payment routing, and cascading.
Knowledge of PCI DSS, KYC/AML, and secure payment data processing.
Experience with observability tools such as Prometheus, Grafana, OpenTelemetry, Loki, or Jaeger.
Experience mentoring engineers and improving engineering practices.
Understanding of threat modeling, attack surface analysis, secrets management, and the principle of least privilege.

Interview stages:
🤝 Interview with Recruiter.
🧠 Technical Interview.
💙 Offer.

We offer:
🌴 24 paid vacation days, 14 sick days, and 5 days off.
⏰ Flexible start of the working day — from 9:00 to 11:00.
🏥 Medical insurance.
💰 Bonuses and performance-based rewards.
🐶 Office in the center of Kyiv — pets are welcome, we are pet-friendly.
💆 Lounge area in the office to recharge during the day.
🎾 Padel tennis, football, and training at the polygon for those who enjoy active leisure.
📚 Learning compensation, internal meetups and workshops, as well as access to the corporate LMS with courses.
🎁 Corporate currency that can be exchanged for merch, gifts, or additional benefits.