Senior Backend Developer (Nest.js / Express.js)
Location: Warsaw (On-site)
Company: GB2B
Industry: iGaming / Platform Development
GB2B empowers iGaming companies to deliver seamless player experiences and operate with absolute confidence.
As we continue to scale and build the next generation of high-performance platform technologies, we’re looking for a Senior Backend Developer to join our mission.
Responsibilities
- Build, maintain, and optimize backend services using Node.js (Nest.js / Express.js)
- Improve existing systems, resolve complex issues, and contribute to new high-performance platform features
- Design and implement scalable architectures for high-traffic, distributed environments
- Work with PostgreSQL and MongoDB, ensuring performance, optimization, and data integrity
- Manage and deploy cloud-based architectures (AWS / GCP / Azure)
- Contribute to performance tuning, load balancing, and Kubernetes-based deployments
- Collaborate closely with cross-functional teams to deliver secure, reliable, and maintainable solutions
- Apply best practices for data privacy, security, and high-availability services
- Participate in technical and architectural discussions, helping evaluate trade-offs between system performance, reliability, scalability, and business needs
Requirements
- 5+ years of experience building backend systems with Node.js, using Nest.js or Express.js
- Strong expertise with PostgreSQL, MongoDB, and cloud database environments
- Proven experience with high-traffic, large-scale, and complex system architectures
- Hands-on experience with Kubernetes, load balancing, and performance scaling strategies
- Solid understanding of system design, data structures, and cloud infrastructure
- Familiarity with security standards and data protection principles
- Demonstrated platform and product mindset — ability to assess technical decisions in the context of reliability, scalability, user impact, and business constraints
- Excellent problem-solving skills with a proactive, solution-oriented approach
- Strong communication skills and ability to collaborate effectively within cross-functional teams
Why Join GB2B
- Be part of an innovative team shaping the future of the iGaming industry
- Work on meaningful, high-impact projects at global scale
- Competitive, rewarding compensation package
If building reliable, scalable backend systems motivates you, we’d love to meet you.
