Technical Support Engineer – IoT Connectivity & Debugging

Technical Support Engineer – IoT Connectivity & Debugging You don't just escalate. You dig until you find it! Onomondo is on a mission to revolutionise global IoT connectivity. We're here to redefine how connected devices communicate, and we need great engineering leaders to help us push the boundaries of what's possible. Our work directly impacts millions of devices globally, ensuring seamless, low-latency, and highly available connectivity for mission-critical applications. Our services enable secure authentication, signalling, and messaging for devices using Onomondo SIM cards, across 680+ networks in 180+ countries. We are now hiring a Support Engineer (IoT Connectivity) at our HQ on Islands Brygge. About the Role This is a deep technical support role sitting at the intersection of IoT devices, cellular networks, and real engineering. You'll own complex customer issues end-to-end — from first report to confirmed root cause — working across a domain that spans device behaviour, core network signalling, and TCP/IP performance. This is a focused, high-autonomy role where cases land with you and stay with you. Some will take days. That's not a problem — that's the point. The problems are genuinely hard: attach failures, roaming issues, TCP performance degradation, and API and connectivity combinations that don't behave as they should. No two look the same, and there's no playbook that covers them all. You'll work directly with our highest-tier enterprise customers and alongside technical counterparts at major global network partners. These are senior, technical conversations — not ticket updates. When you crack a case that's had a customer blocked for days, they know it. You're not anonymous here. This is a long-term path for someone who loves deep technical support, not a stepping stone out of it. You will be the one who owns the hardest cases, shapes how investigations are run, and becomes a true domain expert in IoT connectivity, signalling, and device behaviour. What You Will Be Doing Own complex issues end-to-end — from the first escalation through to root cause and resolution, with full accountability throughout Read and interpret packet captures (pcap/Wireshark) across TCP, UDP, GTP, Diameter, GSM_MAP, and more Debug device behaviour — AT commands, modem state machines, attach/detach flows, bearer setup Trace signalling through the core network — you'll understand what HSS, PGW, and DRA do and where things break Write scripts and tooling to accelerate your own investigations — parsing pcaps, diffing log files, automating comparisons across hundreds of captures Reproduce issues in lab environments, not just theorise about them Translate technical findings into clear, precise language for customers and internal stakeholders Engage engineers and R&D when you've hit the edges of what you can resolve alone — arriving with evidence, a clear hypothesis, and specific questions, not just "I'm stuck" What You Bring Technical foundations Hands-on experience with TCP/IP, data plane troubleshooting, and reading raw packet traces Familiarity with cellular concepts: attach flows, PDN, bearer, IMSI/IMEI, APN, QoS Working knowledge of at least one of: SS7/MAP, Diameter, GTPv1/v2, TCP/UDP packets and network flows Experience debugging IoT devices or modems (Quectel, Sierra Wireless, u-blox, or similar) is a strong plus Coding ability You bring near-engineer coding ability - building Python, bash, or whatever the problem calls for from scratch, including custom tooling to drive your own investigations. Mindset You look at a pcap and form a hypothesis before reaching for Google You don't stop at "it works elsewhere" — you ask why and build the diff You treat a reproducible test case as the beginning of the investigation, not the end You write things down — findings, dead ends, steps taken — so knowledge doesn't disappear You can work methodically through something you've never seen before, without needing a playbook to follow Nice to have