Software Engineer Senior I

Summary

Join Kooth, a rapidly growing digital mental health platform, as a Senior Full-Stack Software Engineer! Based remotely in the UK, you will play a key role in designing and building scalable systems to support young people. This hands-on position offers significant impact, contributing to the development of meaningful and empathetic digital products. You will lead by example in best practices, mentor colleagues, and contribute to technical discussions. The role requires 3+ years of full-stack experience with specific technologies and a commitment to quality and continuous improvement. Kooth offers competitive salary, generous leave, professional development, and comprehensive benefits.

Requirements

• 3+ years of hands-on experience in full-stack software development in a product-oriented environment
• Proficient in TypeScript, Node.js, and either React or React Native (or able to ramp up quickly with a solid engineering foundation), as well as database technologies such as PostgreSQL and experience in delivering a web or native mobile application
• Deep enthusiasm for full-stack software engineering with strong problem-solving capabilities
• Solid understanding of modern system architecture and the ability to contribute to its evolution
• Commitment to quality, with experience shipping maintainable, scalable, and well-tested code
• Ownership mentality with a focus on pragmatic delivery and continuous improvement
• Skilled in agile practices, data-informed decision-making, and building reliability
• Excellent communication and collaboration skills, including mentoring and inspiring peers
• A team player who values collective success and nurtures a positive, inclusive engineering culture
• A proactive approach to solving technical challenges and influencing engineering direction
• Focus on pragmatic delivery, able to take ownership appropriately
• Strong communication skills, builds great colleague relationships across disciplines

Responsibilities

• Designing and building RESTful Node APIs, React frontends, and/or React Native mobile apps—contributing to system design and architectural evolution
• Leading by example in trunk-based development, automated testing, CI/CD, and infrastructure-as-code principles
• Taking ownership of performance, resilience, observability, maintainability, security, and accessibility
• Building and operating a suite of Node.js backend services, React-based web apps, and React Native mobile experiences that form the backbone of our mental health platform
• Taking end-to-end ownership of features, from idea through to production, with a strong sense of accountability and user impact
• Improving the systems you work on by applying thoughtful, pragmatic solutions to technical challenges
• Actively collaborating across disciplines and mentoring colleagues through pairing, code reviews, and knowledge-sharing
• Driving a shared understanding of user needs, commercial priorities, and how technical decisions influence business outcomes
• Contributing to and occasionally leading technical discussions and decisions
• Staying current with industry best practices in engineering, CI/CD, and architecture
• Supporting onboarding and professional growth of junior engineers and new hires
• Participating in the out-of-hours on-call rota and improving system reliability and incident response processes
• Continuously improving the systems you work on, applying a thoughtful and pragmatic approach to technical tradeoffs

Preferred Qualifications

• Deep experience with React or React Native in production environments
• Experience operating production systems and improving them through observability, testing, and thoughtful design
• A track record of delivering product improvements that tie into measurable business and user outcomes
• Familiarity with cross-platform design, mobile/web accessibility, and monorepos
• Expertise in trunk-based development, test automation and infrastructure as code
• Experience with scalable system design and architecture patterns
• Exposure to cloud-native technologies, particularly GCP or AWS with Kubernetes
• Leadership in cross-functional initiatives or technical working groups

Benefits

• Competitive Salary: Up to £75,000 dependant on experience
• Generous Annual Leave: Enjoy 28 days of annual leave, in addition to public holidays, providing you ample time to recharge and spend quality moments with your loved ones
• Professional Development: Benefit from our yearly professional training programmes, tailored to your career aspirations and designed to enhance your skills and knowledge
• Financial Security: Secure your financial future with our pension contributions and annual company share option awards, giving you a stake in the success of the company
• Health and Well-being: Prioritize your health and well-being with our comprehensive Health Shield cover and access to an Employee Assistance Programme (EAP). The EAP offers 24/7 telephone mental health support and access to GP consultations, ensuring your mental and physical health are taken care of
• Life Assurance: Gain peace of mind knowing that you're covered with life assurance, providing up to four times your annual salary to your loved ones in the unfortunate event of your passing
• Flexible Working: Embrace the flexibility of remote working, allowing you to create a work-life balance that suits your needs and maximizes your productivity