Senior Backend Software Engineer - Golang or Java

1GLOBAL is a technology-driven global mobile communications leader, built to help enterprises unlock the full potential of mobile connectivity at scale. Powered by a best-in-class telecom platform – including our own owned and operated global mobile core network, a full end-to-end eSIM technology stack, and an extensive portfolio of telecom licenses – 1GLOBAL operates as a fully regulated telecommunications provider across 40 countries worldwide. Combined with our privileged access to the global wholesale telecom market, this positions us uniquely to deliver seamless, compliant, and scalable connectivity solutions anywhere in the world.

We serve many of the world’s leading banks, enterprises, and digital-first businesses, including neo-banks, fast moving consumer goods companies, travel leaders, and payment service providers. Today, 1GLOBAL connects more than 70 million people and devices globally, enabling our customers to launch, scale, and innovate with confidence in the mobile ecosystem.

1GLOBAL is a profitable, fast-growing business. With full-year revenues exceeding US$200 million and profits of over US$25 million, we generate strong cash flows and fund our growth independently—continuously investing in infrastructure, platform innovation, and global expansion. Recent years have marked a defining phase in our journey, with major enterprise and mass-consumer client wins accelerating our evolution into a global mobile connectivity powerhouse, purpose-built to enable consumer brands to enter and succeed with their own telecommunications offerings.

Founded in 2022 by experienced technology entrepreneurs Hakan Koç and Pyrros Koussios, 1GLOBAL has rapidly emerged as a European technology leader shaping the future of global telecommunications. We operate as a fully regulated Mobile Virtual Network Operator (MVNO) in 12 countries and as a regulated telecom operator in an additional 28 markets. Headquartered in the Netherlands, with world-class R&D hubs in Lisbon, Berlin, and São Paulo, our team of close to 500 experts across 15 countries is united by a single ambition: to redefine global mobile connectivity through technology, scale, and execution excellence.

Position Overview

You will be joining a dynamic team at the forefront of developing and maintaining our Network API, xSIM Management System, and Recording Platforms. The Network API powers critical systems and services that enable the creation, configuration, and real-time monitoring of subscriber configurations across a wide array of business scenarios. These include enterprise solutions, IoT deployments, regulatory compliance, and recording services, ensuring seamless connectivity for everyone and everything. Our xSIM Management System is a high-performance, low-latency platform designed to handle hundreds of transactions per second, keeping all xSIMs accurately updated in real time. Meanwhile, our Recording Platforms deliver robust Mobile Compliance & Recording capabilities tailored for financial institutions, automatically capturing client and employee interactions either on-premises or through our secure cloud infrastructure.

We run a multi-site platform, following strict security requirements, provide the service to customers around the world and manage millions of subscriber profiles. We embrace a highly collaborative and diverse environment, value teamwork, autonomy and hold ourselves accountable for our deliverables and customer success.

Key Responsibilities

• Provide accurate effort estimates to support roadmap planning and effective expectation management.
• Design and implement resilient, scalable, secure, and fault-tolerant architectures to ensure system reliability and performance.
• Develop new features and support existing systems across the Network API, xSIM Management System, and Recording Platforms.
• Contribute with small, incremental enhancements that seamlessly integrate into the established codebases.
• Maintain and update existing solutions to keep them modern, efficient, and reliable.
• Collaborate with team members to ensure smooth development processes and shared understanding.
• Write and maintain comprehensive tests to ensure fast regression and reliable validation of new features.
• Implement procedures and metrics to enable effective monitoring and observability of platform contributions.
• Participate in code reviews to promote high standards of code quality, readability, and maintainability.
• Take ownership of the quality and outcomes of your work, ensuring fully functional end-to-end flows.
• Create and maintain accurate, up-to-date technical documentation.
• Actively contribute to team discussions, with a mindset for continuous improvement and openness to new ideas or technologies.

Requirements:
Must Have

• 6+ years of professional experience in backend development, preferably with Go (Golang). Strong Java experience with willing to learn Go is also welcome.
• Strong understanding of concurrency models, with practical experience in implementing asynchronous workflows, inter-process communication, and synchronisation techniques.
• Skilled in designing, building, and consuming RESTful APIs, following best practices for API design and performance optimisation.
• Proven experience working with databases, both relational (e.g., PostgreSQL) and non-relational (e.g., Redis, MongoDB, DynamoDB), including data modelling, query optimisation, and performance tuning.
• Experienced in writing unit tests, integration tests, and benchmarks, with a test-driven development mindset.
• Comfortable with networking protocols and distributed communication patterns (e.g., gRPC, WebSockets, TCP/UDP).
• Experienced in building scalable microservices architectures and distributed systems.
• Knowledgeable in applying software engineering best practices and design patterns for maintainable, testable code.
• Skilled in using DevOps tools and practices, including Docker, CI/CD pipelines, and Infrastructure as Code.
• Familiar with Git workflows and collaborative development processes such as pull requests, code reviews, and agile methodologies.
• Demonstrated accountability for technical outcomes and ownership of end-to-end feature delivery.
• Effective communicator in English, both written and verbal, suitable for a remote and largely asynchronous work environment.

Nice to Have

• Proficient in writing idiomatic Go code, with solid understanding of the language’s core features such as interfaces, structs, composition, and error handling.
• Competent in profiling and performance tuning using Go’s built-in tools such as pprof and trace, with a focus on optimisation.
• Demonstrated experience with event-driven architectures, including the implementation of producers and consumers using platforms like Kafka, RabbitMQ, or ActiveMQ.
• Solid hands-on experience deploying, monitoring, and maintaining applications on Kubernetes.
• Working knowledge of cloud platforms (e.g., AWS, GCP, Azure, Oracle Cloud) with experience deploying cloud-native applications.
• Hands-on experience with observability and monitoring tools like Prometheus and Grafana.
• Experience with MSML and SIP is a strong plus

Benefits:
What we offer?

• CLT contract — enjoy job stability and reliable benefits that value your work
• Quarterly performance bonuses to reward your hard work and achievements
• Meal allowance paid into Caju card — R$100 per working day
• Health insurance with SulAmérica — 50% covered by the company
• Extended parental leave - 180 days of maternity leave and 20 days of paternity leave.
• Daycare allowance provided to mothers with children under 3 years old — R$500 per month per child
• Kickstart your journey with an exciting welcome onboarding trip to one of our European offices (Lisbon or Berlin)!

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.