Senior Full Stack Engineer (Frontend-Oriented, AI-First Product Team)

At Similarweb, we are revolutionizing the way businesses interact with the digital world by revealing to them everything that happens online. Our unique data and solutions empower over 4,300 customers globally, including industry giants like Google, eBay, and Adidas, to make game-changing decisions that drive their digital strategies. In 2021, we went public on the New York Stock Exchange, and we continue to reach new heights! Come work alongside Similarwebbers across the globe who are bright, curious, practical and good people. Why is this role so important at Similarweb? We are looking for a Senior Full Stack Engineer with strong frontend and product orientation to build modern, scalable, AI-powered product experiences. This role combines deep expertise in client-side architecture and user experience with the ability to contribute across backend services, APIs, and platform infrastructure. You will work closely with product, design, backend, and data/AI teams to deliver end-to-end features while driving engineering excellence and leveraging AI throughout the development lifecycle. We are looking for engineers who are passionate about building great products, care deeply about user experience, and enjoy owning solutions from concept to production. So, what will you be doing all day? Full Stack Engineering Build end-to-end product experiences across frontend and backend systems Develop modern web applications using React, TypeScript, Vite, and NestJS Design scalable frontend architectures, reusable UI components, and shared platform capabilities Own complex features from concept to production across client and server layers Design and implement APIs, business logic, and integrations with internal and external services Optimize application performance, reliability, accessibility, and developer experience Collaborate closely with product, design, data, and infrastructure teams Contribute to testing strategies, observability, deployment pipelines, and platform improvements Lead technical decisions spanning frontend and backend domains Drive engineering best practices, maintainability, and scalability across the codebase Backend & Platform Development Design, build, and maintain backend services using NestJS Define API contracts and integration patterns across systems Participate in architectural decisions across frontend and backend systems Build scalable and reliable services supporting AI-powered product experiences Contribute to authentication, authorization, and platform capabilities Understand and optimize system performance across the full stack Support production operations, monitoring, troubleshooting, and incident resolution when needed Product & UX Translate product requirements into polished and intuitive user experiences Work closely with product designers to improve usability and interaction quality Balance speed, quality, technical excellence, and business impact Advocate for accessible, user-centric, and data-informed interfaces Contribute product ideas and technical insights throughout the product lifecycle Technical Leadership Provide technical leadership across frontend and backend domains Mentor engineers and conduct high-quality code reviews Drive architectural discussions and engineering best practices Improve testing, observability, CI/CD, and application reliability Promote ownership and accountability from design through production Help establish scalable engineering processes and standards AI-Augmented Engineering Use AI coding tools effectively (Cursor, Copilot, Claude, ChatGPT, etc.) Critically evaluate, validate, and improve AI-generated code Design efficient workflows for AI-assisted development Integrate AI capabilities into product experiences where relevant Understand the limitations, risks, and tradeoffs of LLM-based systems Contribute to engineering productivity through AI tooling and automation Collaborate with AI and data teams to build AI-native product experiences This is the perfect job for