Software Engineer, Java

Upstream is a global leader in mobile marketing automation and digital service innovation, enabling Mobile Network Operators (MNOs) and brands to grow revenue, improve customer engagement and succeed in the digital economy. With over two decades of experience and operations spanning 45+ markets across Africa, Latin America, Asia, Europe, and the Middle East, we are a trusted partner to more than 60 MNOs worldwide. Headquartered in Athens, Greece, and with regional hubs in London, Dubai, Johannesburg, Lagos, São Paulo and Rio de Janeiro, Upstream combines global expertise with deep local insight. Our end-to-end approach encompasses strategy, creative development, technical deployment, campaign execution, and ongoing optimization, ensuring seamless, scalable, and performance-driven service delivery. We are looking for an enthusiastic Software Engineer, Java, to join our Software Development team. You will be part of a very competent team that works on mission-critical applications, contributing to all phases of the development process. You will be responsible for Java application development, supporting business objectives while providing expertise in the full software development lifecycle, from concept and design to testing.

Responsibilities

Develop on high-volume, low-latency applications for mission-critical systems, delivering high-availability and performance; Write well-designed, testable, efficient software modules; Ensure designs comply with specifications and that specifications cover all needed aspects of the implementation; Create/review design documentation and provide feedback on test plans.

Requirements

BSc/MSc in Computer Science, Software Engineering, or equivalent; 3-5 years of full-time professional experience in designing and developing applications using the Java ecosystem; Solid background in Object-Oriented Analysis and Design; Experience with popular Java frameworks and technologies such as Spring Framework, JPA/Hibernate, JEE; Good knowledge of SQL and RDBMS concepts; Experience with HTTP APIs; Basic understanding of concurrency concepts; Working knowledge of Maven, Git, and CI/CD principles.

Nice to have

Asynchronous messaging technologies, such as RabbitMQ and Kafka; Horizontally scalable, distributed, microservices architectures; NoSQL databases such as Redis, Elasticsearch; Caching technologies, such as Hazelcast, EhCache; Strong team player with good communication skills; Eager to work with leading-edge technologies; Analytical thinker with attention to detail; Reliable and dedicated professional with clear thinking and strong attention to detail; Able to multitask and thrive in a dynamic environment as well as balance and prioritize activities to ensure critical items are addressed

Benefits

Competitive base salary and benefits