Mobile Core Engineer (Sim for Things)

Proximus Global, combining the strengths of Telesign, BICS, and Route Mobile, is shaping the future of communications and digital identity. Our mission is simple : to enable seamless global connectivity and trusted engagements that power the world's interactions. Together, our solutions fuel innovation across the world's largest companies and emerging brands. With a truly global reach, we enable businesses to create engaging customer experiences while integrating fraud protection across the entire lifecycle. Our portfolio covers global voice, messaging and data connectivity, alongside 5G and IoT solutions. It also includes digital identity, verification and CPaaS platforms for personalised, omnichannel engagement. Through these capabilities, we help businesses and communities stay connected, secure and ready to grow. Today, we reach more than 5 billion subscribers, secure over 180 billion transactions every year, and connect more than 1,000 destinations worldwide — delivering on our commitment to connect, protect and engage everywhere. Key highlights Powering more than 13 billion digital communications every month Supporting over 3,500 active customers through a presence in 50+ global offices across 100+ countries Managing 50% of global roaming data traffic and connecting 150 million IoT devices Driving innovation in 5G , private networks and IoT, reinforcing our position in next-generation communications Why Proximus Global? Global & Inclusive Work with diverse teams across 100+ countries, in a truly international and connected environment. Ownership & Trust Take initiative, make decisions and own your impact with real autonomy. Innovation with Purpose Contribute to meaningful solutions in global connectivity, combining technology, platforms and expertise across Proximus Global. Growth Mindset Continuously learn, challenge the status quo, and grow across our global organisation. Please note: this role requires working from the Brussels office 2 to 3 days per week . It is not a fully remote position and is offered on a permanent contract (not freelance). About the role At Proximus Global, we’re looking for a Mobile Core Engineer to join our SIM for Things (SFT) team. In this role, you will design and deliver end-to-end mobile core solutions for IoT connectivity, working at the intersection of technology, product, and operations. From requirements to production, you’ll take ownership of solutions and help shape the evolution of our platforms. You’ll collaborate closely with cross-functional teams to ensure high-quality, scalable solutions and a seamless customer experience. What you’ll do Design and validate technical solutions aligned with business, operational, and regulatory requirements Contribute to the roadmap and evolution of mobile core platforms Lead or support end-to-end implementation projects, including design, rollout and optimisation Draft and review functional & technical specifications and RFPs Drive architecture and impact analysis, and produce technical documentation Collaborate closely with operations, product, and marketing teams Act as a technical reference point, supporting internal and external stakeholders What you bring Experience & technical expertise Degree in Telecommunications, IT, or related field ~6+ years of experience in a telecom or IT environment Strong experience with IoT / M2M connectivity platforms, including SFT Solid understanding of eSIM & Remote SIM Provisioning, including GSMA SGP.31/32 SIM lifecycle management & provisioning workflows Multi-tenant environments & large-scale device connectivity Experience with SIM file systems, applets, and SIM ordering processes Nice to have Knowledge of mobile core components, including 2G/3G/LTE, HLR, HSS, PCRF, etc. Understanding of protocols: HTTP, SS7, Diameter, MAP, GTP Experience in roaming, IoT, MVNO/MVNE environments End-to-end view of mobile core architecture and call flows Your soft skills Strong communicator, able to translate technical concepts for different audiences Collaborative team player in an international environment Customer-focused with a strong sense of ownership Analytical, structured, and solution-oriented Proactive, with solid organisation and project management skills Comfortable navigating complexity and prioritising effectively Your Benefits A competitive base salary and short-term incentives, including a yearly bonus linked to individual and company performance Comprehensive insurances including hospitalization insurance, outpatient care insurance, life insurance, disability insurance and travel insurance, fully funded by PXG A supplementary pension plan, fully funded by PXG A flexible mobility package including a company car or car allowance, a mobility budget for flexible commuting including a fuel card, bike lease options, etc. A telco offer including free internet at home, budget for a mobile phone, a monthly phone plan and many discounts on the Proximus products catalog Additional benefits such as meal and eco vouchers, 32 vacation days, corporate discounts through Benefits@Work, … Wellbeing at work: yoga and pilates classes, corporate events, etc. Discover Proximus Global Get a flavour of Proximus Global activities by watching our video. ▶ Watch the video — Published by Proximus. 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