Job Summary: We are seeking a Founding Backend Tech Lead to design, build, and own the system architecture and backend of an innovative AI-powered conversational platform. Key Highlights: 1. Founding role with real impact on millions of users 2. Design and build the core architecture of an AI product 3. Lead end-to-end backend and microservices Our client is an innovative tech startup that has developed a conversational platform powered by AI agents assisting visitors in real time—enhancing user experience and generating actionable data for operators. We are looking for a Founding Backend Tech Lead who wants to design, build, and own the company’s entire system architecture and backend. This is a founding role, where you will shape the core platform powering real-time AI assistants used by millions of visitors in shopping malls, airports, stadiums, and tourist complexes. You will be responsible for the backend, APIs, microservices, data flows, real-time orchestration, and end-to-end ML integrations—ensuring performance, security, and scalability as we expand internationally. This role sits at the intersection of AI, product engineering, infrastructure, data architecture, and ML operations (MLOps). Key Responsibilities: * Architect and lead end-to-end backend and microservices. * Build scalable APIs, workers, queues, and real-time systems on GCP + Cloud Run + Cloud SQL. * Implement integrations with CRMs, CMSs, booking systems, loyalty platforms, and external APIs. * Develop backend support for AI agents: retrieval APIs, embeddings, vector databases, and inference services. * Build and maintain event pipelines for analytics, ML, and product insights. * Ensure system security, observability, monitoring, logging, and CI/CD best practices. * Collaborate with Product and AI teams to define technical architecture and rapidly implement new features. __________________________________________________________________________ What We Offer: * Competitive salary package aligned with your experience. * Phantom Shares: We want you to be a stakeholder in the project and benefit from the company’s growth. * Work model: Hybrid 50% Remote/Office in Barcelona. * Founding role. * Real Impact: Participate in launching pioneering technology affecting millions of users in the physical world. Technical Requirements: * Experience: 5+ years building scalable backend systems. * Must-have technologies: Python (FastAPI or Django), SQL (Postgres/MySQL), and REST/GraphQL APIs. * Infrastructure: Experience with microservices and Cloud Run. * Databases: Strong knowledge of schema design, migrations, indexing, and performance optimization. * Integrations: Experience integrating external APIs (OAuth, webhooks). * AI: Familiarity with LLM integrations, retrieval flows, or vector databases such as Qdrant. __________________________________________________________________________ Product & Leadership * Prior experience as a backend or platform lead in a startup, or having led a technical project from inception to delivery. * Ability to act as Tech Lead: make decisions, review architecture, guide junior/mid engineers, and drive delivery timelines. * Preference for simple, reliable, and resilient systems. - Autonomous, fast-paced, and comfortable in zero-to-one environments—with some initial ambiguity. * Clear, proactive, and hands-on communicator. __________________________________________________________________________ Additional Skills * Frontend technologies (desirable but not required): TypeScript, JavaScript, and React. * Competitive salary package aligned with your experience. * Phantom Shares: We want you to be a stakeholder in the project and benefit from the company’s growth. * Work model: Hybrid 50% Remote/Office in Barcelona. * Founding role. * Real Impact: Participate in launching pioneering technology affecting millions of users in the physical world.