Senior Software Engineer, Java

Who We Are 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. The role We are looking for an enthusiastic Senior Software Engineer to join our Software Development team in Athens, Greece. As a Senior Software Engineer, you will be part of a very competent team that works on mission - critical applications contributing in all phases of the development process. You will be responsible for Java application development, supporting business objectives while providing expertise in full software development lifecycle, from concept and design, to testing. Your main responsibilities will be: Write well designed, testable, efficient software modulesEnsure designs are in compliance with specifications and that specifications cover all needed aspects of the implementationPrepare and produce releases of software componentsProvide support for production systemsCreate/ review design documentation and provide feedback on test plansSupport continuous improvement by investigating alternatives and technologies and presenting these for architectural reviewSupport and coach junior developers Requirements BSc/MSc in Computer Science, Software Engineering or equivalent5+ years of full time professional experience in designing and developing applications using the Java ecosystemSolid background in Object Oriented Analysis and DesignExperience with popular Java frameworks and technologies such as Spring Framework, JPA/HibernateExperience with asynchronous messaging technologies (e.g. RabbitMQ, Kafka)Experience designing and developing HTTP web servicesExcellent knowledge of SQL and RDBMS conceptsWorking knowledge of Maven, Git and Continuous Delivery principles Experience in the following will be extra appreciated: NoSQL databases such as Redis, Elasticsearch, CouchbaseCaching technologies, such as Hazelcast, EhCacheHorizontally scalable, distributed, microservices architectures You will be an excellent fit for our team if you are: Strong team player with good communication skillsEager to work with leading-edge technologiesReliable and dedicated professional with clear thinking and strong attention to detailAble to work well under pressure and meeting deadlines in sometimes challenging situationsAble to multitask and thrive in a dynamic environment as well as balance and prioritize activities to ensure critical items are addressed Benefits We offer a competitive base salary and benefits, directly dependent on the candidate's qualifications and skills. The real excitement comes from working closely with a dynamic, smart, agile, and highly motivated team in a competitive and fast-paced environment. Follow us on LinkedIn and stay updated on our latest news. Upstream is an equal-opportunity employer. Upstream is an equal-opportunity employer. The Company does not discriminate on the basis of race, color, creed, pregnancy, religion, gender, national origin, age, disability, marital status, or any other legally protected status. The Company also makes reasonable accommodations for disabled employees. Finally, the Company prohibits the harassment of any individual based on their protected status. This policy applies to all areas of personnel actions, including recruitment, hiring, training, promotion, compensation, benefits, transfer, and social and recreational programs