Senior Full Stack Developer (Contractor)

About Kisi We are Kisi, a physical security tech company revolutionizing how businesses access and secure their spaces. Founded in 2012, with headquarters in Brooklyn, an office in Stockholm, and a global team, we create innovative, award-winning hardware and compliance-certified software that enable seamless, cloud-based access to offices, facilities, and buildings. Our mission is to ensure ease of access and remote space management, fostering a future where spaces are securely connected and accessible without boundaries. At Kisi, you’ll join a creative and innovative team with a flat hierarchy, work closely with our co-founders, and enjoy the freedom to work your way with a strong sense of ownership. If you’re passionate about cutting-edge technology and want to be part of a dynamic team that’s making the world more secure and accessible, we want to hear from you! About the role We are seeking a highly motivated Senior Full Stack Developer to join our dynamic team and help expand our innovative product portfolio. Our mission is to seamlessly connect people and spaces through an open platform that includes cloud-based video intercoms, wireless locks, and third-party access control systems. The ideal candidate will possess a robust background in full-stack web development, proficiency in modern frameworks and best practices, and a passion for creating cutting-edge user experiences. In this role, you will design, develop, and optimize sophisticated web applications, mentor junior developers, and collaborate with cross-functional teams to ensure the highest standards of performance, reliability, and security. What you'll do Coordinate with product and engineering managers to align development with business goals. Architect, design, and implement efficient, scalable, and responsive web applications using modern frameworks and technologies across teams (e.g. design, platform). Monitor relevant metrics and identify areas for improvement, e.g. according to web performance best practices. Address bugs and performance issues through automated unit, integration, and end-to-end testing. Address vulnerabilities, apply updates, and maintain security documentation proactively. Mentor junior developers, interns, conduct code reviews, and offer guidance on complex tasks. Qualifications At least 5+ years of experience Strong proficiency in Ruby/TypeScript and experience with modern frontend development tools Experience with relational database systems Outstanding communication skills, with the ability to articulate technical concepts to both technical and non-technical stakeholders. Excellent organizational and project management abilities, ensuring efficient task prioritization and timely delivery. Commitment to continuous learning and staying current with emerging trends and best practices. Application process Application : Submit your application through our online form and include a link to your LinkedIn profile. CV Screening : Our recruiting team will review your resume to assess your background, skills, and fit for the role. Technical test task : You’ll receive a short, take-home technical assignment designed to simulate the kinds of problems you’ll tackle on the job. Technical and behavioral interview : Meet one-on-one (via video call) with your hiring manager to walk through your test task, discuss your approach, and dive deeper into your technical experience. Culture interview : Have a conversation with cross-functional team members to learn more about our values, work style, and company culture—and for us to learn more about what motivates you. Offer : If it’s a mutual fit, we’ll extend a formal offer and welcome you to the Kisi team. Please note that this is a contractor position