Senior Java Backend Developer (Node.js / TypeScript)

Senior Java Backend Developer (Node.js / TypeScript)

Miejsce pracy: Warszawa

Technologies we use

Expected

• Java
• Spring Boot
• Spring Framework
• Docker
• API
• REST API
• Spring Security
• OAuth2
• Kafka
• Node.js

About the project

We have an exciting opportunity with one of our clients who specialize in telecommunications and large-scale digital commerce platforms, we are looking for a talented Backend Developer with strong Java backend expertise to fill the position of Backend Developer Senior.

The Digital Domain team operates mission-critical BFF (Backend for Frontend) services supporting checkout, customer management, and commerce processes for millions of users.

The role includes backend development, system integrations, API design, event-driven architecture, and production support activities. Candidates with Node.js / TypeScript experience will be strongly preferred due to the ongoing technology transformation toward a unified Node.js / TypeScript ecosystem.

The team works in a hybrid model and collaborates closely with architects, frontend teams, product teams, and technical leads.

Your responsibilities

• Design, develop, and maintain scalable backend services using Java 21+ and Spring Boot 3.x
• Build and integrate REST APIs and support integrations with multiple internal and external systems
• Work with event-driven and distributed architectures, including asynchronous communication and messaging systems
• Support production environments through monitoring, troubleshooting, observability, and continuous improvement activities
• Collaborate with architects, frontend developers, product teams, and technical leads in agile delivery teams
• Participate in technology transformation initiatives toward Node.js / TypeScript ecosystem
• Write unit and integration tests while ensuring high code quality and resilience standards
• Contribute to production-grade engineering practices, reliability, and maintainability of services

Our requirements

• API design and system integrations
• Event-driven architecture and distributed systems
• Asynchronous flows and messaging concepts
• Unit and integration testing
• Monitoring, logging, troubleshooting, and observability
• Java 21+
• Spring Boot 3.x
• REST API / OpenAPI
• Spring Security / OAuth2 / JWT
• Distributed system design experience
• Production ownership and incident resolution
• Mentoring and technical leadership experience
• Technology migration/transformation experience
• Ability to influence engineering standards and best practices

Optional

• Commercial experience with Node.js and TypeScript
• Experience with Express, Fastify, or NestJS frameworks
• Knowledge of Kafka or RabbitMQ
• Experience with Docker and Kubernetes
• Familiarity with GraphQL
• Experience with Terraform and Infrastructure as Code
• Knowledge of OpenTelemetry and distributed tracing
• Experience with Jest or Vitest testing frameworks
• Understanding of npm / pnpm ecosystem

This is how we organize our work

This is how we work

• at the client's site

SQUARE ONE RESOURCES sp. z o.o.

At Square One Poland we link IT experts with the business. With over 25 years of experience, we specialize in recruitment processes on a global scale. Despite years of experience, we still have a startup DNA and this is our advantage. Our offices are located in London and Warsaw, however, we can reach clients from all over the world, from start-ups to big worldwide corporations.