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 Integration Engineer (Full-Stack) to join a US-based company building the next generation of enterprise real estate technology, to build and maintain integrations between the product and third-party systems.
About the Project
This role sits at the intersection of product, engineering, and external platforms and is heavily focused on practical API integration work. You'll work with existing product and engineering teams to understand integration goals, investigate external APIs, map and transform data, implement integration logic, troubleshoot issues, and help deliver reliable integration experiences. This is a great role for a strong mid-level engineer who is comfortable working independently once the goal and general direction are clear.
Location: Warsaw (B2B)
Heavy use of AI tools for implementation is welcome, as long as you can explain, debug, and modify the code it generates
Responsibilities:
- Own the end-to-end lifecycle of integrations, from design and development to deployment and ongoing optimization
- Build and maintain scalable integrations with third-party platforms, APIs, and external services
- Develop full-stack features using Node.js, React, and TypeScript, with a strong focus on backend architecture
- Design, optimize, and maintain database schemas and queries using PostgreSQL
- Partner cross-functionally with Product, Design, and Engineering to deliver seamless, user-centric integration experiences
- Diagnose and resolve complex integration issues, ensuring high reliability and uptime
- Improve system performance, scalability, and observability across integration workflows
- Establish best practices for integration architecture, error handling, and asynchronous processing
- Manage multiple integration projects simultaneously, balancing speed with quality and long-term maintainability
Requirements
Must-have:
- Strong software engineering fundamentals, including APIs, data models, databases, authentication concepts, and application architecture
- Hands-on experience working with APIs and third-party integrations
- Solid full-stack experience, with the ability to contribute across backend and frontend when needed
- Experience with Node.js, TypeScript, PostgreSQL, and React
- Proven ability to debug issues across multiple systems and services
- Product-oriented mindset with a focus on delivering real user value, not just technical output
- Ability to operate independently, prioritize effectively, and manage multiple workstreams
- Strong communication skills, fluent English, with 4-5 hours of overlap with US Central Time
Nice-to-have:
- Experience integrating with CRM platforms or enterprise SaaS tools
- Familiarity with REST APIs, webhooks, event-driven architectures, and async workflows
- Experience in high-growth or fast-paced startup environments
- Exposure to observability tools, monitoring systems, and reliability best practices
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