Senior Full-Stack Engineer (Java and React)

Description

We are seeking a Senior Full-Stack Engineer with strong expertise in Java, Spring Boot, Kafka, microservices, and modern software architecture to deliver scalable solutions across enterprise banking and financial services environments. The ideal candidate brings valuable Financial Services experience spanning Investment Banking, Commercial Banking, Digital Banking, Asset Management, and financial messaging platforms, providing a strong understanding of complex financial ecosystems. This role combines solid backend engineering capabilities with cloud-native experience, AI-assisted development practices, and exposure to React-based frontend technologies, enabling effective contribution to end-to-end platform development. This role offers a hybrid model, with 3 days per week working from the client's office in Kraków or Wrocław, Poland. Responsibilities Design and develop scalable backend services using Java, Spring Boot, and microservices-based architectures Build and maintain modern, responsive front-end applications using ReactJS and related technologies Deliver end-to-end platform features across enterprise banking and financial services environments Implement event-driven solutions leveraging Kafka and integrate with PostgreSQL databases Apply AI-assisted development practices to improve productivity and code quality Develop and maintain automated tests to ensure reliability and quality of the codebase Collaborate with cross-functional teams to define, design, and ship new features Contribute to architectural decisions and promote best practices in software engineering Ensure solutions align with the complexities of financial ecosystems and business requirements Requirements 7+ years of backend development experience with Java 17+, Spring Boot 3+, and microservices-based architectures Proficiency in ReactJS, Redux, and TypeScript Skills in HTML5, CSS3, and modern JavaScript (ES6+) Knowledge of PostgreSQL and Kafka Background in automated testing using JUnit 5, Mockito, Testcontainers, or similar tools Familiarity with AI engineering tools such as GHCP CLI Understanding of Generative AI concepts and capabilities (frontier models) Strong English communication skills (B2 level or higher) Nice to have Exposure to.NET and C# Familiarity with Splunk, Grafana, and App Insights Practical knowledge of Kubernetes, Helm, and Terraform Experience with GitLab CI/CD pipelines for build, test, packaging, and deployment automation Strong domain understanding of the Stock Borrow Loan business, including structured context in codebases (AGENTS.md, skills)

Requirements

• 7+ years of backend development experience with Java 17+, Spring Boot 3+, and microservices-based architectures

• Proficiency in ReactJS, Redux, and TypeScript

• Skills in HTML5, CSS3, and modern JavaScript (ES6+)

• Knowledge of PostgreSQL and Kafka

• Background in automated testing using JUnit 5, Mockito, Testcontainers, or similar tools

• Familiarity with AI engineering tools such as GHCP CLI

• Understanding of Generative AI concepts and capabilities (frontier models)

• Strong English communication skills (B2 level or higher)

Responsibilities

• Design and develop scalable backend services using Java, Spring Boot, and microservices-based architectures

• Build and maintain modern, responsive front-end applications using ReactJS and related technologies

• Deliver end-to-end platform features across enterprise banking and financial services environments

• Implement event-driven solutions leveraging Kafka and integrate with PostgreSQL databases

• Apply AI-assisted development practices to improve productivity and code quality

• Develop and maintain automated tests to ensure reliability and quality of the codebase

• Collaborate with cross-functional teams to define, design, and ship new features

• Contribute to architectural decisions and promote best practices in software engineering

• Ensure solutions align with the complexities of financial ecosystems and business requirements

Seniority

• Senior

Nice to have

• Exposure to.NET and C#

• Familiarity with Splunk, Grafana, and App Insights

• Practical knowledge of Kubernetes, Helm, and Terraform

• Experience with GitLab CI/CD pipelines for build, test, packaging, and deployment automation

• Strong domain understanding of the Stock Borrow Loan business, including structured context in codebases (AGENTS.md, skills)