Mobile Developer Engineer

My team is shaping the future of IoT security. Location: Sant Joan Despí (BCN), ES G+D makes the lives of billions of people around the world more secure. We create trust in the digital age with integrated security technologies in Digital Security, Financial Platforms, and Currency Technology. With over 170 years of experience and more than 14,000 employees in 40 countries, we are a reliable partner for customers seeking innovative solutions in SecurityTech. We are looking for a Mobile Developer Engineer to join our team in Barcelona. In this role you will be responsible for the end-to-end development of secure, high-quality mobile SDKs and applications for Android (Kotlin) and/or iOS (Swift), while emphasizing code quality, testing best practices, and collaboration. Key Responsibilities - Design, develop, and maintain native mobile SDKs and libraries in Kotlin and Swift. - Create native mobile applications that showcase these SDKs. - Contribute to code reviews, pair programming, TDD and E2E testing. - Integrate hardware features such as secure elements and NFC. - Work with RESTful APIs and collaborate with backend teams. - Set up and master CI/CD pipelines, contribute to documentation, and perform secure code reviews. - Follow Scrum workflows and participate in daily stand-ups. - Deliver features from ideation to deployment with a focus on security and compliance. - Optimize the CI/CD pipeline for quality and speed. Must-Have Qualifications - Proficient in native Android (Kotlin) and/or iOS (Swift) development. - Willingness to assist across both platforms if needed. - Experience with mobile development tooling such as IDEs, test frameworks, and emulators. Nice-to-Haves - Cross-platform experience, preferably with Flutter. - Familiarity with hardware features (NFC, BLE) and native code integration. - Understanding of Docker, Figma-based UI implementation, Rust, smart cards, secure elements, or byte-level debugging of binary protocols. Ideal Candidate You write secure, test-driven code, enjoy collaborating with teammates, mentor others, and are comfortable exploring new tools and technologies in a fast-paced mobile environment. What you will do in the first 90 days Days 0-30: Orientation & Foundations - Get familiar with company culture and security basics. - Attend intro sessions on password policies, secure code review, incident response. - Run local builds for iOS, Android, and backend. - Review security policies and study product user flows, architecture diagrams, and API specs. - Shadow senior developers and join product demos. Days 31-60: Deepening Skills & First Contributions - Participate in workshops on secure coding and best practices (OWASP Mobile Top Risks). - Write code using TDD for small features and bug fixes. - Engage in pair programming with a mentor focused on security and test cases. - Work with E2E tests, CI/CD, and contribute to them. - Take ownership of a real ticket and participate in a security code review. - Document features and tests. Days 61-90: Autonomous & Secure Contribution - Own delivery of a feature end-to-end. - Fix a medium-level security issue and propose new tests. - Lead a security retrospective or knowledge-sharing session. - Optimize part of the CI/CD workflow (caching, deployment automation, test speed). - Mentor newcomers on secure coding basics. - Help refine Scrum processes and share lessons learned through onboarding documentation. What's great about working with us - Culture and diversity : Join a people-oriented environment with a mix of nationalities, a great team spirit, and flat hierarchies. - Team : Shape our engineering culture and collaborate with a passionate, mission-driven international team. - Global Collaboration : Work with stakeholders worldwide. - Impactful Work : Participate in and shape a global lighthouse project in digital currencies. - Career Development : Benefit