Senior Full Stack Engineer (eSIM IoT Squad)

Onomondo is on a mission to revolutionize global IoT connectivity. We’re here to redefine how connected devices communicate and we need great engineers 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, signaling and messaging for devices using Onomondo SIM cards, across 680+ networks in 180+ countries.

At Onomondo, we're tearing down the walls of closed, inflexible IoT connectivity, and we’re doing it with code. As part of our newly formed eSIM IoT Squad, you’ll help build the world’s first fully open, vendor-agnostic eSIM IoT platform, based on GSMA SGP.32. By building this platform, we are enabling true flexibility for businesses deploying connected devices, a new developer

experience in IoT, with simple APIs, great tooling and instant provisioning workflows.

This platform puts the control back in the hands of those who build and deploy connected devices, from electric vehicles and smart meters to global logistics and consumer wearables.

This isn’t just about writing code, it’s about rewriting the rules of how global devices connect, scale and operate. You’ll work alongside a small, focused team (Product Manager + 1 Engineer) in a startup-like environment within a scale-up, building 0→1 products with global reach.

What you’ll be doing

Platform Development: Design and build the foundational backend systems and APIs that power Onomondo’s eSIM IoT platform. These services will enable communication and integration with SIM vendors, mobile network operators (MNOs) and device firmware, supporting provisioning, profile lifecycle management and secure connectivity across millions of devices.

Translate specs into magic: Together with the team, make sense of GSMA SGP.32 standards (like eIM and IPAd) and turn them into clean, scalable, production-grade software.

Device Interoperability: Collaborate with hardware and firmware engineers to ensure seamless SIM lifecycle management, provisioning and profile activation.

Solve for the real world: Get deep into how our customers build and scale their devices and craft platform features that feel intuitive, flexible and helpful.

Observability: Design tooling and telemetry to empower diagnostics, provisioning insights, and debugging at scale.

Bake in security: Implement smart, secure provisioning and authentication flows that protect devices and customers from day one.

What you bring

• Full-stack engineering skills (5+ years), with solid backend experience (preferably Go and JavaScript) and proficiency in frontend technologies.
• Systems thinking. Able to reason across hardware, network, software and systems integrations boundaries.
• Experience working with cloud-native architecture and container orchestration (e.g., Kubernetes).
• Builder mindset. Comfort navigating early-stage ambiguity, rapidly prototyping ideas and iterating based on feedback from internal users, partners and commercial teams. This requires thoughtful trade-offs and a pragmatic approach.

Complementary skills

• You've worked in a high-growth SaaS company
• Interest in IaC, specifically Terraform/OpenTofu
• Experience with eSIM stack components (LPA, IPAd, eIM) or telecom infrastructure
• Contributions to open source projects or standards bodies.

Why join Onomondo?

• A playful, ambitious culture where people are trusted to do what they do best
• A workspace that’s one-of-a-kind, in both design and energy
• A team that’s small, sharp, and all-in on shipping meaningful things fast, with room for your voice and fingerprints on what we build.
• Legendary lunches, snack heaven, and events that actually bring people together
• Real ownership and impact, especially in this role, where you'll help define a brand new product category in one of tech’s fastest-growing spaces.

In-house technologies: Kubernetes, Terraform, AWS, Grafana, Node.JS, Redis, and PostgreSQL.

In-house languages: C, JavaScript, Erlang, Go etc.

Our hiring process

We care deeply about creating a fair and inclusive process.

That means:

• We don’t need your picture or cover letter—just your CV
• We select candidates based on skills and relevant work experience for the role.

We’re fast but thoughtful—our goal is to ensure you feel informed, respected, and excited throughout the journey.

1. 30-minute screening call with our recruiter, Christian Payne
2. Technical interview (in-person) with 2 engineering team members (1hr)
3. Culture Interview and Hire Manager Interview (1hr 20 mins). 30 mins with Mille Hertz (Chief People Officer) and a 50-minute interview with Dana (VP of Engineering)
4. Final stage - Meet our leadership for 30 minutes, onsite - Meet with our Co-Founder, Michael Karlsen and our CTO, Henrik Aagaard

Ready to Make an Impact?

Please send us your CV, and let's start the conversation.

Learn more about us and other opportunities at onomondo.com/careers