Senior Frontend Developer (React.js / Next.js)

Keylr is a B2B Marketplace and SaaS platform transforming the UK property management industry. We're building a modern platform that enables property managers, landlords, estate agencies, and service providers to manage jobs, suppliers, compliance, payments, and operations from one intelligent system. We're an early-stage, product-focused startup building the platform from the ground up and are looking for a talented Senior Frontend Developer to join our core engineering team. Role Overview We're looking for a Senior Frontend Developer who can take ownership of the frontend architecture and build a scalable, modern, and high-performance application using the latest frontend technologies. You'll work closely with our backend developer, product team, and founders to deliver a world-class SaaS product. What You'll Be Working On ● Build scalable, responsive web applications using React.js, Next.js, TypeScript, and Tailwind CSS. ● Convert AI-generated (Claude) designs and specifications into clean, maintainable, and production-ready frontend code. ● Develop reusable UI components and maintain a scalable frontend architecture. ● Integrate REST APIs with backend services. ● Build responsive experiences that work seamlessly across desktop, tablet, and mobile devices. ● Collaborate closely with backend developers and product stakeholders. ● Optimize application performance, accessibility, and user experience. ● Participate in code reviews, technical discussions, and architectural decisions. ● Follow best practices for frontend development, testing, and maintainability. Required Skills ● 5+ years of professional frontend development experience. ● Strong expertise in: ○ React.js ○ Next.js ○ TypeScript ○ JavaScript (ES6+) ○ Tailwind CSS ● Experience building SaaS products, marketplaces, or other complex web applications. ● Experience translating AI-generated (Claude) or Figma designs into production-ready interfaces. ● Strong understanding of responsive and mobile-first development. ● Experience integrating REST APIs. ● Good understanding of authentication methods (JWT, OAuth). ● Experience with Git and collaborative development workflows. ● Strong debugging, problem-solving, and communication skills. ● Ability to work independently and take ownership of features. Nice to Have ● Experience with Stripe or other payment gateway integrations. ● Experience with AI APIs (OpenAI, Anthropic, etc.). ● Experience integrating third-party SaaS platforms or CRM systems. ● Experience with React Native. ● Experience with WebSockets or real-time applications. ● Previous startup or product development experience. Working Style Our product designs are primarily created using Claude AI, with supporting product documentation and specifications provided by the team. Your role will be to transform these designs into clean, scalable, and production-ready React/Next.js applications. While we encourage the use of AI development tools where they improve productivity, we're looking for someone who can write high-quality code, make sound technical decisions, and take ownership of the frontend implementation. What We're Looking For We're looking for a developer who enjoys building products from the ground up and wants to make a meaningful impact on an ambitious SaaS platform. You should be proactive, detail-oriented, and comfortable working in a fast-paced startup environment where you'll collaborate closely with the founders and engineering team. You'll have the opportunity to influence technical decisions, contribute to product architecture, and help shape the future of Keylr. If you're passionate about building exceptional user experiences and writing clean, scalable code, we'd love to hear from you.