Embedded Software Engineer - Onomondo

We’re looking for an Embedded Software Engineer with strong C programming experience to join our embedded development team.

You’ll work on Onomondo SoftSIM and other device-related projects in the IoT domain, contributing to high-impact products that tackle deep technical challenges across the cellular ecosystem.

At Onomondo, we are re-implementing traditionally hardware-bound cellular components as fully software-defined components - starting with the SIM. This means working close to the metal: constrained environments, strict specifications (3GPP / ETSI), protocol correctness, security boundaries, and performance-critical code.

This is where you come in.

You’ll contribute to core SIM functionality, write portable, testable embedded C code, and help shape software that runs across a wide range of devices and cellular environments. If you enjoy deep technical problems, precise specifications, and software that replaces hardware, you’ll feel right at home. We have started with the SIM - but we won’t stop there.

What you’ll do

• Developing the next generation of features and integrations for our SoftSIM product lineup

  • Write portable embedded C targeting multiple platforms and toolchains

  • Implement and maintain APDU parsing and command handling

  • Work with low-level memory management

  • Debug protocol flows and edge cases across real cellular networks and devices

• Developing provisioning tooling for developer and production use-cases

• Developing automated test and validation pipelines

Our ideal new colleague

• Experience with C in embedded or system-level environments (C experience is a must)

• Experience working with Zephyr or FreeRTOS

• Familiarity with CI/CD pipelines (e.g. GitHub Actions or Jenkins)

• Bonus points for:

  • familiar with ETSI and 3GPP specifications

  • familiar with Rust and Go programming languages

  • familiar with open-source project contribution

  • experience with embedded security concepts such as secure boot, TF-M, key management, cryptographic accelerator, and OTA updates

• Embrace teamwork, yet self-motivated and able to work autonomously

• Ability to adapt to a fast-paced and dynamic work environment

• Fluent in English

• Must be currently based in Copenhagen, Denmark (or within an hour commutable distance)
  

Why join Onomondo?

We’re not just building another connectivity layer – we’re reimagining how global IoT connectivity works from the ground up. With customers like Maersk and global use cases across industries, we’re tackling problems that have never been solved before.

You will experience:

• 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
  

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.

• 30-minute screening call with our recruiter, Christian Payne

• 1st stage interview (Onsite, 1 hr) with Benjamin (SoftSIM Engineer)

• Technical interview (Onsite, 1 hr) with Benjamin and another team member

• Culture Interview (Onsite 1hr 20 mins) with Henrik (CTO) and an engineering team member

• Final stage - Meet our leadership for 30 minutes, onsite - Meet with our Co-Founder, Michael and our CTO, Henrik.

Ready to Make an Impact?

Send us your CV, and let’s start the conversation.

Note - We review and interview candidates continually, and therefore encourage you to apply at your earliest convenience.

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