Senior Full Stack Developer

About this role

<p class="font-claude-response-body break-words whitespace-normal">At Similarweb, we are revolutionizing the way businesses interact with the digital world by revealing to them everything that happens online.</p> <p class="font-claude-response-body break-words whitespace-normal">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.</p> <p class="font-claude-response-body break-words whitespace-normal">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.</p> <p class="font-claude-response-body break-words whitespace-normal">We are looking for a <strong>Senior Fullstack Engineer with a strong backend orientation</strong> to join the development of our scalable, AI-powered product systems.</p> <p class="font-claude-response-body break-words whitespace-normal"><strong>What You'll Do:</strong></p> <p class="font-claude-response-body break-words whitespace-normal">Join a role that combines deep backend expertise with solid frontend fluency and product thinking, along with the ability to leverage AI tools effectively across the development lifecycle. You will work closely with product, design, frontend, and data/AI teams to build reliable, performant systems and intuitive user experiences, while driving engineering excellence and modern development practices. Your contributions will shape the technical foundation of an AI-first product and directly influence the experience of end users.</p> <p class="font-claude-response-body break-words whitespace-normal"><strong>What does the day to day of a Senior Fullstack Engineer at Similarweb look like:</strong></p> <p class="font-claude-response-body break-words whitespace-normal">Your daily work will span backend architecture, frontend collaboration, and AI-augmented development, engaging directly with the systems that power our product.</p> <p class="font-claude-response-body break-words whitespace-normal">Your role will include:</p> <ul class="[li_&amp;]:mb-0 [li_&amp;]:mt-1 [li_&amp;]:gap-1 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-1 pl-8 mb-3 print:block print:space-y-1"> <li class="font-claude-response-body whitespace-normal break-words pl-2">Design and build scalable, maintainable backend services using NestJS (Node.js/TypeScript) and/or Python</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Own API design, contracts, and versioning across services</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Design and optimize data models, database schemas, and query performance</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Implement authentication, authorization, and secure API integration patterns</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Build reliable data-fetching layers, caching strategies, and async processing (queues, jobs, events)</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Lead backend technical decisions, code quality standards, and system architecture</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Ensure system scalability, fault tolerance, and observability (logging, monitoring, alerting)</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Contribute to CI/CD pipelines and deployment practices for backend services</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Collaborate on frontend applications built with React, TypeScript, and Vite, and contribute to API contracts from the consumer's perspective</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Partner with frontend engineers to align on data shapes, performance, and UX constraints</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Translate product requirements into robust, scalable technical solutions, working closely with product and design</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Conduct high-quality code reviews and drive architectural discussions and best practices</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Improve testing, observability, CI/CD, and system reliability across the team</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Use AI coding tools effectively in daily development work (Cursor, Copilot, Claude, ChatGPT, etc.), critically evaluating and refining AI-generated code, especially for backend logic and data integrity</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Design efficient personal/team workflows for AI-assisted development and contribute to engineering productivity through AI tooling and automation</li> </ul> <p class="font-claude-response-body break-words whitespace-normal"><strong>What does the ideal candidate look like:</strong></p> <ul class="[li_&amp;]:mb-0 [li_&amp;]:mt-1 [li_&amp;]:gap-1 [&amp;:not(:last-child)_ul]:pb-1 [&amp;:not(:last-child)_ol]:pb-1 list-disc flex flex-col gap-1 pl-8 mb-3 print:block print:space-y-1"> <li class="font-claude-response-body whitespace-normal break-words pl-2">5+ years of fullstack engineering experience, with a strong backend focus</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Strong proficiency in Node.js, TypeScript, and NestJS; Python proficiency also welcome (or equivalent backend framework)</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Solid working proficiency in React and modern frontend fundamentals (HTML, CSS)</li> <li class="font-claude-response-body whitespace-normal break-words pl-2">Experie