Payne Talent are recruiting on behalf of our client for a Senior React/React Native Developer.

Join a fast-moving startup dedicated to revolutionising credentials, digital access, and data encryption.

We’re looking for a React/React Native developer to manage our web and mobile development.

This isn’t just a coding role – we need someone who brings product thinking, business awareness, and the ability to work cross-functionally.

You will work closely with our Tech Lead, Head of Engineering, Product Designer, and product managers in a collaborative environment that values open communication and innovation.

In this key role, you will help shape the future of our product by driving front-end development, contributing to architectural decisions, and ensuring high performance and scalability as we grow.

Your proactive mindset and passion for quality code will significantly impact our success.

About the Role

• Take ownership of the entire frontend and mobile development, working closely with the Tech Lead, Head of Engineering, and Product Designer. This role is not just about coding—it's about product thinking, business awareness, and cross-functional collaboration to shape and implement front-end solutions that directly impact the user experience.

• Develop, maintain, and optimise React and React Native applications, focusing on enhancing the existing mobile app and browser extension.

• Take ownership of front-end code quality by writing, testing, reviewing code, and proactively identifying and resolving performance and caching issues to support scaling for larger customers.

• Participate actively in daily stand-ups, technical discussions, and brainstorming sessions, contributing ideas and solutions to ongoing challenges, technical debt, product improvements, and new feature development.

• Engage directly with customer feedback and support teams to quickly address bugs, improve user flows, and adapt the product based on real-world usage.

• Work primarily on-site in the Copenhagen office to foster close collaboration, open communication, and a dynamic startup culture.

• In the medium term, lead initiatives to optimise front-end architecture and system design, ensuring security and encryption standards are upheld.

• Over time, grow into a key technical expert and go-to person for front-end development, potentially taking on leadership responsibilities as the team expands.

Your Experience

• Minimum 5+ years of professional experience in React development, with strong proficiency in React Native and a proven track record of taking ownership of web and mobile development

• Ideally good experience with security concepts, including encryption (AES, RSA), secure data handling and storage (Keychain, Keystore, extension storage), authentication flows (OAuth2, OIDC), secure token handling (JWT), and XSS/CSRF mitigation

• Strong communicator, able to collaborate with non-technical stakeholders and engage directly with customers

• Product-minded, curious about the 'why' behind features, and focused on business and user impact

• Proven ability to develop and maintain browser extensions or similar front-end applications, with knowledge of extension APIs, storage, permissions, and sandboxing

• Experience with performance optimisation, caching strategies, and managing data flow for scalable, enterprise-scale applications

• Solid understanding of architecture and system design principles, including modular, maintainable frontends, monorepos, code splitting, lazy loading, and large-scale project structure

• Comfortable giving and receiving feedback, challenging assumptions, and discussing feasibility, effort vs. impact, and long-term maintainability

• Experience working within CI/CD pipelines, code review workflows, and release cycles for mobile apps and extensions

• Strong experience writing and maintaining automated tests (unit, integration, and UI), and responsible for end-to-end testing of your own code
  

What's in it for you?

• Join a fast-moving startup environment where your work quickly goes into production and makes a real impact

• Be part of a small, close-knit product and engineering team based in Copenhagen, fostering a collaborative and open culture

• Enjoy a high degree of autonomy and influence over product design and technical decisions, including direct involvement in product trio's

• Work onsite full-time to engage in dynamic whiteboard sessions, spontaneous brainstorming, and close collaboration with product designers, customer success, and backend developers

• Take ownership of your code with responsibility for testing and quality, eliminating bureaucratic layers and accelerating development cycles

• Thrive in a culture that values proactive communication, curiosity, and a sense of humour, where your ideas and feedback are welcomed and acted upon

• Opportunity to grow into a key front-end expert role with potential future leadership responsibilities as the company scales

• Supportive environment open to continuous learning, including potential funding for relevant courses or certifications related to encryption and performance optimisation

• Experience a transparent and flexible work culture that encourages innovation and improvement without rigid processes or micromanagement

Our Lean Hiring Process

1. 30-minute screening call with our recruiter, Christian Payne

2. 1 hour onsite meeting with Christian (Head of Engineering) and Vadim (Lead Backend Developer)

3. Final meeting with Sanne (Chief Product Officer) and a few others from your new team