Senior Back-End Developer (Warsaw)
First seen by Alion on Oct 20, 2026.
🚀 Senior Back End Engineer (Node.js): Shape the Backend of a Global B2B Platform
The challenge:
Picture an enterprise platform used by customers worldwide, processing huge volumes of data through distributed systems where performance, scalability, and reliability aren’t nice-to-haves but the baseline.
Our client is an established international technology company building a sophisticated B2B software platform. The environment is data-intensive and complex: mature production systems live side by side with ongoing innovation. The team is constantly developing new capabilities, optimizing existing services, and improving the underlying architecture.
Your role:
We’re looking for an experienced Senior Back End Engineer to join a product engineering team working on large-scale software systems. The role is predominantly backend, with occasional frontend work when a project needs it.
You’ll take end-to-end ownership of your solutions: from requirements analysis and system design to implementation and deployment. You’ll collaborate with cross-functional teams, influence architectural decisions, and work with a high degree of autonomy. We’re looking for someone independent and proactive, with strong technical judgment and a product-oriented mindset.
What you’ll do:
Build and maintain scalable production services in TypeScript and Node.js
Own system-design decisions for new capabilities and integrate them with existing infrastructure
Turn product and engineering requirements into effective technical solutions
Design and optimize PostgreSQL queries, indexes, and database performance
Contribute to React frontend work when the project calls for it
Work with DevOps on deployments, observability, capacity, and production readiness
Handle feature development, bug fixes, security improvements, and production patches
Evaluate architectural alternatives and communicate trade-offs in business terms
Use AI development tools daily for planning, coding, and testing
Join the on-call rotation and help resolve critical production issues
What you bring
5+ years of backend development on production systems at scale, with a solid understanding of distributed systems
Strong hands-on TypeScript and Node.js expertise
Solid system-design skills and the ability to explain decisions and trade-offs
Strong PostgreSQL skills: complex queries, optimization, indexing, performance tuning
Familiarity with React and willingness to work on the frontend when needed
Familiarity with CI/CD, Docker or Kubernetes, and observability
Ability to work independently and collaborate across teams
Product-oriented thinking that connects technical choices to business and user needs
Practical experience with AI-assisted development tools
Bonus points:
✦ Microsoft Azure or another major cloud platform
✦ Redis, Elasticsearch, or ClickHouse
✦ Deeper DevOps experience: infrastructure and deployment workflows
Why us:
20 days of vacation per year, plus official national holidays in your country of residence
Full accounting and legal support in all countries where we operate
A powerful workstation and access to coworking space when needed
If you want real ownership, interesting scale, and a say in how the system evolves, let’s talk.