Senior FullStack Engineer in London

AI Factory, an Italian spin-off of AI Venture Builder specialized in developing and deploying AI solutions for enterprises, is looking for a Senior FullStack Engineer with at least 5 years of experience, with full mastery of both frontend and backend, and a strong aptitude for analysis and design of complex systems.

What you will do:

• Analyze requirements, design architectures, and lead the full lifecycle of software projects, from requirements gathering to production deployment.
• Design and implement distributed and replicated middleware and backend applications, leveraging Redis as a cache and Redis Streams (including consumer groups) for coordination across instances.
• Design and build modern, responsive web interfaces for AI-powered products, with a focus on usability, performance, and accessibility.
• Build and maintain a shared Design System across products, with a component library documented in Storybook, ensuring visual consistency and a high-quality developer experience.
• Build conversational UIs and LLM interaction interfaces, handling response streaming (SSE, WebSocket), feedback loops, and prompt-driven UX patterns.
• Integrate RAG pipelines and semantic search into user-facing experiences — e.g. document Q&A, augmented search, knowledge assistants.
• Implement integrations with AI model APIs (OpenAI, Anthropic, etc.) across both frontend and backend layers.
• Ensure security, GDPR compliance, and privacy protection across the entire application stack.
• Package complete solutions as SaaS or on-premise products, managing automated deployment and versioning.
• Collaborate with AI/ML and design teams to translate model capabilities into usable product features.

Requirements Analysis and Design:

• Ability to analyze functional and non-functional requirements and translate them into solid, scalable software architectures.
• Experience in designing distributed systems, with attention to scalability, resilience, and observability.
• Product-oriented mindset, with the ability to balance technical debt, feature development, and system stability.
• At least 3 products successfully brought to production, with ownership over the full lifecycle.

Backend:

• 5 years of experience in backend development with any language (Java, JavaScript, TypeScript, C, or equivalent).
• At least 2 years of experience with TypeScript as the primary backend technology.
• Strong knowledge of Python as a secondary technology (e.g. FastAPI, scripting, AI/ML integration).
• Proficiency with Docker for containerization and a solid understanding of Kubernetes basics for orchestration.
• Experience with Redis (as a cache and as a message broker via Redis Streams and consumer groups), MongoDB, PostgreSQL, and MySQL.
• Solid understanding of communication mechanisms: JWT tokens, REST APIs, and WebSocket.
• Knowledge of application security, GDPR, and privacy by design principles in system design.
• Experience designing and implementing distributed, replicated backend architectures, with proper concurrency management and cross-instance coordination.

Frontend:

• Strong command of TypeScript/JavaScript and major frontend frameworks (React, Angular, Vue, etc.).
• Experience designing and maintaining Design Systems and component libraries, using Storybook for documentation and visual testing.
• Solid knowledge of state management (Zustand, Jotai, or equivalent), frontend performance optimization, and testing approaches (unit, integration, E2E).
• Hands-on experience integrating LLM APIs (OpenAI, Anthropic, Gemini, etc.) and handling streaming responses (SSE, WebSocket).
• Good knowledge of modern CSS, CSS-in-JS (Styled Components, Emotion), or utility-first approaches (Tailwind CSS).

Preferred qualifications:

• Knowledge of prompt engineering techniques and LLM interaction optimization.
• Familiarity with RAG architectures and vector databases.
• Experience with microservices architectures and service mesh.
• Proven experience in designing scalable architectures and managing the full lifecycle of software products.

Contract and compensation:

• Preference for freelancers with a VAT number (Partita IVA); permanent employment contracts also considered based on profile and mutual needs.
• Compensation commensurate with experience and commitment, with the possibility of a customized package discussed during the interview.

Why work with us:

• You will work on real AI-powered products — not prototypes — for companies in industrial, fashion, healthcare, and defense sectors, with thousands of active users.
• You will have full ownership of the technical architecture and the opportunity to design systems end-to-end, from backend infrastructure to user experience.
• You will work closely with cutting-edge AI models and a multidisciplinary team including researchers, ML engineers, and product managers.

Do you want to be part of our team? Apply now!