Senior Java Software Engineer - Global Connectivity Platform

1GLOBAL is a technology-driven global mobile communications provider dedicated to empowering enterprises worldwide to unlock the full growth potential of mobile connectivity. With a best-in-class telecom technology platform, a comprehensive suite of globally viable regulatory licenses, and privileged access to the telecom wholesale market, 1GLOBAL is uniquely positioned to deliver seamless compliance and connectivity solutions. Serving the world’s leading banks, corporations, and digital-first businesses—including neo-banks, travel companies, and payment service providers—1GLOBAL connects over 43 million devices globally.

 
With 2024 full-year revenue exceeding US$100 million and in line to exceed US$200 million in FY25, 1GLOBAL is a profitable business generating significant cash flows to fund its ongoing investments in infrastructure, transformation, and growth. 2024 saw major client wins and marked 1GLOBAL’s evolution from a multi-market telecommunication provider to a global technology-driven mobile connectivity powerhouse.

 
Established in 2022 by experienced tech founders and entrepreneurs Hakan Koç and Pyrros Koussios, 1GLOBAL is a European technology leader driving digital transformation in the global telecommunications market. It operates as a fully regulated Mobile Virtual Network Operator (“MVNO”) in ten countries and as a regulated telecommunications operator in an additional 31 countries. Headquartered in the Netherlands, with world-class R&D hubs in Lisbon, Berlin, and São Paulo, 1GLOBAL employs over 450 experts across 15 countries.

Position Overview
This is a senior, hands-on Java role focused on scalable backend systems, long-term ownership, and real production challenges.

You’ll join a new backend team in Warsaw working on the evolution of our eSIM, global connectivity platform, and IoT solutions.

The role combines:

• scaling and modernizing existing systems,
• building new services and greenfield components,
• and improving reliability, performance, and maintainability across the platform.

As a senior engineer, you’ll also contribute to introducing and evolving testing approaches as systems grow and change.

Our technology stack: Java 17 / 21, Spring / Spring Boot, Hibernate / JPA, Kafka, RabbitMQ, Redis, PostgreSQL, MySQL, AWS, Docker, Kubernetes, Git, Maven, CI/CD pipelines

Fluency in English is essential for this role, please ensure your CV is submitted in English as part of your application.

Key Responsibilities

• Design, build, and maintain Java backend services
• Contribute to architecture decisions with focus on scalability, resiliency, and security
• Work on existing services, legacy modernization, and greenfield initiatives
• Build and integrate REST APIs
• Work with messaging systems and data stores
• Advocate for clean code, testing, and maintainable solutions
• Participate in code reviews and technical discussions
• Collaborate closely with your Team Lead and peers
• Work in an Agile, collaborative environment, contributing to planning and continuous improvement
• Mentor other engineers when needed

Requirements

• 5+ years of professional experience in Java backend development
• Experience working with production backend systems
• Solid understanding of REST APIs, databases, and messaging
• Experience with unit, integration, and e2e testing
• Familiarity with CI/CD pipelines and modern development workflows
• Experience working with Git, Docker, and Kubernetes-based environments
• Good understanding of cloud services and scalable infrastructure
• Ability to work independently and take ownership
• Fluent English (spoken and written)

Benefits

Why 1GLOBAL?

• Growth Opportunities: Advance your career in one of the fastest growing telecommunications companies, expanding over 100% year-on-year under the leadership of successful tech entrepreneurs.
• Major Transaction Exposure: Be in the driver’s seat for transactions that will have an impact on the future telco industry.
• Work with a Talented Team: From the Board and the Founders to the Senior Management Team, you will collaborate daily with the most capable and renowned external advisors, and constantly being exposed to talented and driven individuals.
• Dynamic Work Environment: Thrive in a collaborative, fast-paced workplace where innovation is encouraged, and every contribution counts.
• Professional Development: Work alongside industry experts to enhance your skills and knowledge in a cutting-edge field.
• International Experience: Gain opportunities to work in different 1GLOBAL offices around the world as you grow within the company.
• Open Communication Culture: Join a team where your ideas are heard, and open dialogue is encouraged, fostering a supportive and transparent work environment.
• Get Things Done Attitude: Be part of a results-driven team that values efficiency, creativity, and the drive to make a tangible impact in the industry.

1GLOBAL is an equal opportunity employer, we value your character as much as your talent. Diversity drives our innovation, and we offer a collaborative, dynamic, and international work environment. We are excited for you to join our mission to revolutionise connectivity globally.