Senior Fullstack Engineer

Square One Resources REMOTE WARSAW 2026-09-14

Full Stack software development in enterprise environments.
Modern backend and frontend application development.
Designing and developing REST APIs and integrations.
Cloud and cloud-native technologies.
Microservices and distributed systems.
Enterprise-scale applications and high-availability systems.
Legacy application modernization or technology transformation projects.
CI/CD and modern software development practices.
Working effectively with cross-functional and international teams.

Optional

Previous experience in banking or financial services.
Experience with legacy or mainframe modernization.
Experience integrating modern applications with legacy systems.
Knowledge of cloud migration and application transformation.
Experience with Generative AI / LLM integrations, Azure OpenAI, AWS Bedrock, RAG or similar technologies.
Experience working on large-scale international transformation programs.

Large-scale technology modernization program within the financial services sector. Program focuses on transforming enterprise systems through modern application development, cloud transformation, legacy and mainframe modernization, data migration, modern software architecture, and Generative AI.

,[Design, develop, and maintain modern enterprise applications., Work across both backend and frontend development., Build scalable and secure APIs and system integrations., Develop cloud-native applications and services., Contribute to the modernization of legacy applications and enterprise systems., Participate in the transformation of existing systems into modern architectures, including microservices and event-driven solutions., Collaborate with Solution Architects, Technical Leads, DevOps, Data, Cloud, and Mainframe teams., Support application and data migration initiatives., Ensure high standards of code quality, performance, security, and maintainability., Participate in technical discussions and contribute to architectural decisions., Work in an Agile environment with distributed engineering teams.] Requirements: Fullstack Additionally: Sport subscription, Private healthcare.