At AVSystem, we are a Polish-based company behind a telco industry-leading Unified Management Platform (UMP) product allowing Communication Service Providers automatic setup, upgrades, and monitoring of millions of their client routers.We are seeking a dedicated Senior Integration Software Engineer with a programming & networking background. Your role will focus on:Acting as a principal system engineer, designing and architecting robust integration solutionsWriting code & configuring our platform to customize it to our customers’ needsCooperating directly with our customers during delivery and post-delivery supportKey ResponsibilitiesLead the full project lifecycle, from initial system analysis and design to implementation, deployment, and post-delivery support.Act as a principal system engineer, designing and architecting robust integration solutions that include our platform's GUI.Serve as a primary technical point of contact for clients, managing expectations and ensuring seamless collaboration throughout the entire project.Drive the implementation of complex REST API integrations (both client & server-side) with external systems, ensuring high-quality, scalable code.Cooperating directly with our customers during delivery and post-delivery support.Define and configure platform GUI elements to display, monitor, and report on key router performance indicators (KPIs) in line with customer business needs.Act as a key liaison between the engineering team and business stakeholders, translating complex business requirements into technical specifications.Ensure comprehensive documentation and facilitate knowledge transfer to both customers and internal support teams.Report to the Solution Architect, providing mentorship and conducting code reviews for other Software Engineers to maintain high code quality standards.QualificationsMinimum of 3+ years of professional experience in a Software Engineer or similar role, ideally with a proven track record of delivering complex, multi-system integration projects.Deep expertise in writing code and platform configuration during project delivery.Extensive experience in designing and implementing REST API integrations.Demonstrated ability to work directly with customers, managing project scope and technical expectations.Proficiency in at least one programming language (Python preferred), with a willingness to learn our in-house Scala-based functional language.Strong background in system engineering, including architecture and design of integrated, multi-system environments.Deep knowledge of networking concepts such as TCP/UDP, HTTP(S), and SNMP, and the ability to apply these in real-world integration scenarios.Professional experience in the telecom domain, with specific know-how of systems like ACS, NMS, OSS, or BSS.Fluency in English at a B2/C1 level or higher.What we offer:You’ll have a chance to deepen your expertise in maintenance to help us shape the way we deliver & support critical applications for telecommunications companiesYou’ll help us grow a leading technology IoT / device management company that creates software used by tier-1 telcos (e.g. Orange, Vodafone, AT&T, TMobile) around the world and makes Internet connection possible for millions of end-usersSome usual stuff:Onsite gym and chillout space.Multisport card.Medical care.Kitchen full of snacks and treats (including Good Lood ice cream).Car parking area and bike room.A relaxed work atmosphere – no dress code, no open space.Come join the best!