About Us 1 GLOBALis a technology-driven global mobile communications provider, delivering global connectivity solutions to enterprises and consumers. Powered by a best-in-class telecom platform – including its own owned and operated global mobile core network, fully fledged in-house developed e SIM technology, and an extensive portfolio of telecom licenses – 1 GLOBAL operates as a fully regulated telecommunications provider across 40 countries worldwide.We serve many of the world's leading banks, enterprises, and digital-first businesses, including neo-banks, global fast moving consumer goods companies, travel leaders, and payment service providers. Today, 1 GLOBAL connects more than70 million people and devices globally, enabling our customers to launch, scale, and innovate with confidence in the mobile ecosystem.1 GLOBAL is a profitable, fast-growing business. With full-year revenues in 2025 exceedingUS$200 millionand profits of overUS$25 million, we generate strong cash flows to fund our growth allowing us to continuously invest 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 aspirations to offer telecommunications services to their clients.Founded in 2022 by experienced technology entrepreneurs, Hakan Koçand Pyrros Koussios, 1 GLOBAL has rapidly emerged as a European technology leadershaping 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 to500 experts across 15 countriesis united by a single ambition: to redefine global mobile connectivity through technology, scale, and execution excellence.About the TeamAs a Network Engineering member, in the Voice and Services functional area, you will be responsible to propose, analyze and define the requirements for new and existing services and systems, related with the voice systems under the responsibility of the functional area. Prepare, design, test and provide new solutions or product changes of the already existing portfolio. Define and support the technology evolution roadmap for the systems under the functional area.Participate and support the other functional areas in cross functional projects.About the RoleCollaboration with other Networks teams in defining and managing the projects for delivery of new solutionsProject delivery. Network design. Integration and migration strategy definition. Collaboration with other relevant departments. Responsible for end-to-end deliveryDesign of new consumer and corporate telecom solutionsCreation of technical documentation (HLD's, LLD's, WO's, etc.) and maintain it over the lifecycle of the solutionsPerform implementations in live environment. Understanding of End to End system testing requirementsFollow-up and define Quality and Performance indicatorsCapacity and Performance Analysis, Reporting and Improvement Solution DefinitionService & Resource configuration definition and implementation on requested systemsWork on complex solutions that influence the design of current products and addresses design issues for future products or technologiesClose relationship with external partners like carriers, service providersElaborate, and manage the process, for change requests to current partners in order to meet the network necessitiesControl the network elements roadmap, being responsible for the necessary software/hardware upgrade during the components lifecycleGenerate and implement process improvements, including and especially cross-team processesDocuments the existing technology portfolio and proposes recommendations for improvements and/or alternativesAbout YouMust-havesProven experience on implementation of live solutions on mobile telecom (GSM, UMTS, LTE, IMS), networks design, capacity management, engineering and architectureKnowledge of 3 GPP, GSMA, ITU standards and specificationsExperience in the design, test and operation of NGN based networks, including MSS/MGW, HLR/HSS, SBCExperience in defining, establishing and maintaining voice interconnects, SIP/RTP basedUnderstanding about IMS architecture. Knowledge about Vo IP, Vo LTE, Vo Wi Fi, and Qo SExperience with SMS service configuration and routingIMS Architecture with understanding of IMS nodes including P/S/I-CSCF, Application ServersIMS Protocol Interfaces – Gm Interface, ISC interface, Sh Interface, Cx, SOAP/XML, etc.Experience in mobile services charging (offline, online). Knowledge and experience of OCS and, Ro, Ro+, Ga and Bp interfacesKnowledge and experience with Diameter/SCTP networks and protocolKnowledge and experience with Signaling Gateways and protocols including SS7, SIGTRAN, MAP and CAMELExperience with protocol analyzer tools like Wireshark, Astelia, and ability to use them to troubleshoot networks errors/problems for the mentioned protocolsExperience with ETSI NFV architecture and solutionsFamiliar with MVNO/MVNE/MVNA architecture(s) and landscapeEnglish proficiency mandatory, other languages are a plusDegree in Telecom Engineering or Computer Science or equivalent experienceNice-to-haves+3 years working on telecoms, designing and implementing mobile core networksPrevious experience with Nokia, Oracle and Ribbon IMS productsWhy 1 GLOBAL?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 1 GLOBAL 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.1 GLOBAL 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.