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 , using Nest.js or Express.js