Senior BackEnd Developer

GB2B - GamingB2B; Warszawa; On-site; PLN 240,000 - 360,000; Full time

Benefits offered by this job

Competitive compensation

Job summary

GB2B - GamingB2B is seeking a senior backend engineer to build, optimize, and scale high‑performance services with Node.js (Nest.js / Express.js). You’ll tackle complex problems and contribute to core platform features across the stack.

You will work with PostgreSQL and MongoDB, deploy cloud architectures on AWS / GCP / Azure, and lead Kubernetes deployments, load balancing, and performance tuning for large‑scale systems.

Qualifications

• 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.

Responsibilities

• Build, maintain, and optimize backend services with Node.js (Nest.js/Express.js).
• Improve systems and contribute to new high-performance features.
• Design scalable architectures for high-traffic distributed environments.
• Work with PostgreSQL and MongoDB, ensuring performance and data integrity.
• Manage cloud architectures (AWS / GCP / Azure) deployments.
• Tuning, load balancing, and Kubernetes deployments.
• Collaborate with cross-functional teams to deliver secure, reliable solutions.
• Follow data privacy, security, and high-availability practices.
• Participate in technical discussions balancing performance and business needs.

Skills

Node.js

Nest.js

Express.js

PostgreSQL

MongoDB

Kubernetes

Cloud platforms

Load balancing

Security

Architecture design

Problem solving

Communication

Tools

AWS

GCP

Azure

Job description

• 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.