Mobile SDK Engineer (Android)

Barcelona (Sant Joan Despí) | Hybrid (3 days remote)

We’re looking for a Mobile SDK Engineer to build and maintain secure mobile SDKs for Android (Kotlin).

This is not a traditional mobile app development role focused on UI. You’ll work on reusable SDKs that integrate with backend services and device-level capabilities such as NFC, BLE, and secure elements, requiring strong software engineering, security, and system design skills.

What you’ll do

• Design, develop, and maintain native mobile SDKs (Kotlin)
• Build sample/demo applications to validate SDK functionality
• Integrate mobile solutions with backend services (primarily Golang)
• Work with NFC, BLE, secure elements, and other device-level capabilities
• Contribute to code reviews, TDD, E2E testing, and CI/CD improvements
• Participate in security reviews and secure software development practices
• Collaborate in an Agile/Scrum environment with cross-functional teams

What we’re looking for

• Strong experience in Android (Kotlin)
• Solid software engineering fundamentals and API design experience.
• Experience building reusable libraries, frameworks, or SDKs.
• Interest in security, system-level development, and complex integrations.
• Comfortable working beyond UI-focused mobile development.
• Strong collaboration and problem-solving skills.

Nice to have

• Golang
• Knowledge in iOS (Swift)
• Flutter
• NFC, BLE, Smart Cards
• Secure Elements
• Rust
• Docker
• CI/CD pipelines

Why join us?

• Work on cutting-edge digital currency and security solutions.
• International and collaborative team environment.
• Flexible working model (3 remote days/week).
• Career development and continuous learning opportunities.
• Private benefits, flexible compensation, canteen, and more.