Lead/Senior AI FullStack Software Engineer

About the client: Our customer is the European online car market, with over 30 million monthly users and a presence in 18 countries. As a Lead FullStack Engineer, you will play a pivotal role in shaping the future of online car markets and enhancing the user experience for millions of car buyers and sellers. Responsibilities: • Continue the evolution and scaling of our freshly released, native ChatGPT apps and custom MCP integrations. • Develop and maintain high-traffic, public-facing interfaces hosted on AWS modern cloud infrastructure. • Work heavily with AI agents (Claude Code, ChatGPT/Codex) to maintain and extend a codebase  • Operate with full team autonomy, collaborating closely with the Engineering Manager in a "co-author" environment. • Follow the "you-build-it-you-own-it" philosophy, taking full responsibility for the SDLC and production readiness. • Explore and implement emerging AI frameworks and technologies to keep the product at the forefront of the GenAI market. Requirements: • 7+ years of experience developing reliable, highly available, and scalable software systems. • Strong experience working with AI agents (Claude Code, ChatGPT/Codex) to maintain and extend a codebase • Strong proficiency with backend development using Node.js and TypeScript. • Deep experience with Model Context Protocols (MCP). • Proven track record of using AI tooling (ChatGPT, Codex, Claude Code) for rapid operator-driven development. • Hands-on experience with modern cloud infrastructures, specifically AWS, Terraform, and Docker. • Strong proficiency with frontend development (HTML, CSS, JavaScript) and component-based SSR frameworks like Next.js or React. • Experience with SQL and NoSQL datastores, as well as developing in service-based API environments. • Strong understanding of software architecture, design patterns, and clean code principles. • A modern, energetic mindset with critical thinking and systemic vision skills, the ability to work independently and take high-level ownership. • Experience with formal CI/CD pipelines and monitoring services. • Upper-intermediate English level.