Senior/Staff Mobile SDK Engineer (Android + iOS) - WhiteLabel

Senior/Staff Mobile SDK Engineer (iOS + Android) - WhiteLabel

Team: B2B White-Label VPN Platform

Location: Übach-Palenberg / Onsite

About the Role

We’re building a next-generation white-label VPN platform that allows enterprises to seamlessly embed secure connectivity into their own apps. As a Senior/Staff Mobile SDK Engineer, you will own the development of platform-specific SDK layers that power these integrations across iOS and Android.

This role is deeply focused on SDK and systems-level mobile engineering. You’ll work on networking, performance, and platform abstractions that enable reliable, secure VPN experiences at scale.

What You’ll Do

• Implement and maintain platform-specific SDK wrappers:
• iOS (Swift, Network Extension / NEPacketTunnelProvider)
• Android (Kotlin, VpnService) — strong focus area
• Collaborate closely with core SDK engineers to ensure consistent, clean API design across platforms
• Build abstractions that simplify VPN integration for external developers
• Optimize SDK performance for latency, connection stability, and battery efficiency
• Handle connection lifecycle management, error handling, and edge cases across devices and OS versions
• Contribute to SDK architecture, modularity, and extensibility
• Build and maintain demo integration applications
• Document your components, traits, and implementation details clearly
• Support enterprise clients for integration and platform-specific issues

We approach engineering through the following principles: Testing by default, always CI/CD, data and automation-centered, with security at the core. We empower our engineers to make their own decisions about the tools and technologies that best address the problems they are trying to solve. 

What We’re Looking For

• Strong experience in mobile SDK / library development 
• Good expertise in Android (Kotlin, VpnService) & iOS (Swift & Network Extensive framework)
• Strong understanding of mobile networking and system-level APIs
• Experience designing clean, stable, developer-friendly SDK APIs
• Solid understanding in software design principles and architectures
• Experience with unit testing and test-driven development (TDD) is highly valued
• Strong problem-solving and debugging skills

Nice to Have

• Experience with VPN technologies
• Experience working on B2B / white-label platforms
• Knowledge of mobile security best practices (encryption, secure storage, certificate pinning) 

How we’ll support you

We believe in fostering an environment that empowers decision-making at all levels. Our culture is rooted in the inverted pyramid approach, where the engineers, who have a deep understanding of the product and the customers, are the ones who have the knowledge and the authority to make impactful decisions. 

• We prioritize treating every team member with respect and promote open and constructive feedback, ensuring a culture of trust and transparency
• We encourage learning through experimentation and provide a safe space for everyone to learn from their experiences
• Our managers are dedicated to facilitating career growth and creating an environment that attracts and supports talented engineers

ExpressVPN, a Kape Technologies company, is an equal opportunity employer. We promote equal recruitment and employment opportunities, and do not discriminate based on gender identity and/or expression, age, race, color, disability, culture, religion or belief, family and/or marital status, sexual orientation, or other characteristics protected by applicable law. We celebrate a diverse and inclusive work environment in which applicants and employees are treated with respect and dignity, and excel based on personal merit, qualifications, experience, and performance. 

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Before you apply

• At the moment, we do not sponsor visas in the EU. For Hong Kong, we require at least two years of working experience and a university degree in a related field. For Singapore and the UK, we can only sponsor visas for mid-career or above.
• Please upload your resume as a PDF and do not include any salary or compensation information in it.

ExpressVPN is one of the world’s leading providers of online privacy and security services for consumers. Started in 2009, we’ve grown to have millions of active paying customers, a team of more than 700 people worldwide, and a brand recognized by hundreds of millions of people in 18 languages and more than a hundred countries. We see huge growth in our industry, and are gaining market share through strong execution.