Java Developer

Java Developer – AI project Miejsce pracy: Łódź Technologies we use Expected Java Apache Kafka Redis AWS Optional AI About the project At Sii, we are looking for a Java Developer to join an innovative AI-driven fraud-prevention initiative delivered together with our global telecom client - a company best known worldwide for its cloud communications APIs enabling voice, messaging, and video at massive scale. You will help build intelligent, high-performance systems that protect millions of end users in real time, working in a diverse, supportive, and technology-focused environment. If you enjoy solving complex engineering challenges and want your work to have real-world impact, this is your place. Apply now and build the future with Sii. Sii ensures that all employment-related decisions are made solely on the basis of qualifications and competencies. We are committed to equal treatment of all individuals, regardless of any protected characteristics, and promoting a diverse and inclusive work environment. Your responsibilities Design and implement new backend services that extend an AI-powered fraud detection platform Translate product requirements into scalable technical solutions in close cooperation with product and analytics teams Develop high-performance, cloud-ready Java services handling large volumes of real-time events Take ownership of features from architecture design through deployment and production monitoring Continuously improve system reliability, performance, and detection accuracy using data-driven feedback Our requirements At least 5 years of commercial experience as a Java Developer in complex backend systems Hands-on experience with Kafka, Redis, and AWS in production-grade environments Solid understanding of distributed, high-throughput, and event-driven architectures Experience with multi-threaded applications, RESTful services, and scalable backend design Good command of English (B2/C1), enabling effective collaboration in an international team Residing in Poland required Optional Experience working with or integrating AI / Machine Learning systems What we offer Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022 Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more Comfortable workplace – class A offices or remote work Dozens of fascinating projects for prestigious brands from all over the world – you can change them thanks to Job Changer application PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers Investment in your growth – meetups, webinars, training platform and technology blog – you choose Fantastic atmosphere created by all Sii Power People Recruitment stages Send your CV Talk to us about your expectations Learn more about our projects and choose the best Start your adventure with Sii Sii Sp. z o.o. Sii is the leading technology consulting, digital transformation, engineering, and business services vendor in Poland. We already employ more than 7 300 professionals and implement projects in a variety of industries for clients from many countries around the world. The Great Place to Work title, won 10 times in a row, proves that at Sii, we create a friendly work environment. Sii ensures that all employment-related decisions are made solely on the basis of qualifications and competencies. We are committed to equal treatment of all individuals, regardless of any protected characteristics, and promoting a diverse and inclusive work environment.