Senior Firmware Developer — Smartcard & Mobile Credentials (m/f/d)

Unlock the future of digital security with us!

We are a pioneer in digital locking technology and, with a team of over 550 employees, we ensure that people's lives become safer and more comfortable. We don't just open doors; we open paths to more protected and intelligent living spaces. We achieve this through continuous innovation, team spirit, and a deeply rooted passion for the industry.

As a Senior Firmware Developer, you will design and implement C++ application firmware on microcontrollers (ARM Cortex-M) running an RTOS. Your focus will be on application-level features and the integration of physical and smartphone-based credential processing flows (Mifare DESFire, HCE, mobile wallets).

Sounds exciting? Then become part of our journey!

• Firmware Development: Implement C++ application-layer firmware on an RTOS (tasking, IPC, power-aware scheduling).
• Credential Logic: Develop application logic for existing (Mifare DESFire) and future standards: app/file model, access conditions, personalization, and lifecycle management.
• Connectivity & Workflows: Integrate NFC/BLE/WLAN stacks and mobile credential workflows (provisioning, HCE, revocation).
• Security Implementation: Interface with secure elements / SAMs for key storage and transaction offload. Implement secure boot, signed/encrypted OTA, and application-level runtime protections.
• Software Maintenance: Enhance and maintain internal software suites (C++, C#).
• Testing & CI/CD: Build tests and CI/CD artifacts; use protocol sniffers and hardware debuggers for validation.
• Collaboration: Work closely with mobile, backend, hardware, and QA teams; produce technical and security documentation.

• Experience: + 5 years of embedded firmware experience.
• Core Skills: Strong C++ experience for microcontrollers in resource-constrained environments and practical RTOS experience (Zephyr is an advantage).
• RFID/NFC: Hands-on RFID / NFC experience (ISO 14443, Mifare DESFire EVx preferred).
• Mobile Credentials: Experience with smartphone credential flows (mobile wallets, HCE, provisioning).
• Security: Familiarity with applied cryptography in embedded systems (secure messaging, AES/HMAC, key usage), secure elements / SAM integration, secure boot, and OTA.
• Tools: Debugging skills (JTAG/SWD, logic analyser) and embedded CI/CD experience.
• Languages: Good German and strong English skills.
• Nice to have: Deep Mifare DESFire EVx personalization experience, low-power design, mobile platform SDKs/APIs, knowledge of access control standards, security compliance (CRA, NIST, ETSI), and familiarity with Git, Jira, and embedded test frameworks.

• Modern Tech Stack & Impact// Work in a high-innovation, security-relevant environment with professional test infrastructure and the latest tools.
• Work-Life-Balance // Flexitime model including time off in lieu, remote work possible (1 day/ week), 30 days vacation without probationary period ban.
• Growth & Development // Structured & inspiring onboarding process, hands-on training, access to Busuu, Allegion Academy & LinkedIn Learning, mentoring on development and career paths
• Sustainable mobility // Cost-effective leasing of job bikes and e-bikes
• Health // €30 gross fitness allowance per month, employee assistance program for all life issues, free drinks & fresh fruit.
• Family & More // Up to €250 gross childcare allowance per month, company pension subsidy (€40 plus 20% of the conversion amount), exclusive employee discounts
• Culture // Inspiring spirit, flat organizational structures, a bright team from 17 nations, great helpfulness & cohesion, many great events

Our colleagues provide insights into the development department.