Senior Back-End (API) Developer (Node.js)

About the Position

We are Source Angel - a Danish-rooted software company with development centers in Ukraine, Poland, and Romania. For 10+ years, we've been building dedicated tech teams for global clients, focusing on long-term partnerships and a strong people-first culture.

We foster an environment of respect, transparency, and professional growth, offering engineers freedom with responsibility, collaborative Scandinavian leadership, and an international mindset.

We are looking for an experienced Senior Back-End (API) Engineer to join a US-based company building the next generation of enterprise real estate technology. The platform helps real estate professionals streamline the entire buying and selling journey by unifying data, marketing, and transaction workflows into one powerful system. It's a product-driven team with a modern stack and a strong engineering culture.

About the Project

We're looking for a backend engineer who lives and breathes clean architecture, loves solving complex data problems, and wants to build high-impact systems used by top agents across the United States. If you're passionate about Node.js, PostgreSQL, scalable APIs, and performance optimization, you'll feel right at home here.

Location: Warsaw (B2B)

Responsibilities

• Architect, design, and maintain core services supporting the CRM and Marketing platforms
• Build advanced, scalable data models tailored to the evolving needs of the real estate industry
• Write efficient, high-performance SQL queries and optimize database operations
• Develop high-quality features with robust unit and integration testing
• Collaborate with Customer Success to understand real-world agent workflows and improve user experience
• Influence architectural decisions to support long-term maintainability and growth
• Partner with front-end developers and cross-functional teams to build cohesive, elegant solutions
• Stay on top of industry trends and contribute ideas for new features and backend improvements
• Lead projects when needed and help continuously level up the engineering culture

Requirements

Must-have:

• Deep experience with JavaScript and Node.js
• Strong proficiency with PostgreSQL and SQL performance tuning (including pure SQL, no ORM)
• A solid background in designing, building, and testing scalable backend services
• Experience building and consuming APIs
• A collaborative mindset and strong communication skills
• Creativity in solving complex technical challenges
• 5-7+ years of relevant experience; Bachelor's degree preferred
• Fluent English, with 4-5 hours of overlap with US Central Time

Nice-to-have:

• Experience with RabbitMQ and Redis
• Experience working on highly data-intensive production systems
• Experience taking full ownership of a feature from planning through production with minimal oversight

We Offer

• Exciting projects with dynamic clients
• We provide the necessary equipment for your work
• For B2B contractors, we also assist with opening and maintaining your sole proprietorship (jednoosobowa działalność gospodarcza) in Poland
• An attractive salary package matching your experience and responsibilities
• Office located centrally in Warsaw
• 20 days of paid vacation
• Paid sick leave
• Medical insurance