Senior Product Engineer (Castilla-La Mancha)
12 hours ago
Toledo
Senior Product Engineer (AI-Native)Location: Remote (Within Spain)Contract: Freelance/ContractWe’re searching for a Product Engineer to support in building a multiplatform AI-powered document system, serving hundreds of thousands of users every month.Key ResponsibilitiesBuild and maintain the core multiplatform document system, owning features end-to-end from idea to production across React frontends, Node.Js/Express backends, and Postgre SQL/Databricks data layersDesign and orchestrate agentic AI workflows using Lang Graph, Claude Agent SDK, and MCP protocols; integrate LLMs into product features via prompt chains, tool calling, and function executionProactively instrument features, measure impact, seek user feedback, and iterate based on what you discover treating metrics as a compass, not a report cardBuild, maintain, and extend automation pipelines connected to AI agents, external APIs, webhooks, and cloud services on GCPContribute to database schema design (Postgre SQL, Big Query), build and maintain RESTful APIs, and help manage cloud infrastructure on Google Cloud PlatformCollaborate with engineers, designers, and leadership to shape the product roadmapRequired Experience2–5 years of full-stack experience in a high-output team, with the ability to balance speed and qualityDeep Python, Type Script, and React proficiency frontend (Hooks, Context API, Vite, Shadcn UI) and backend (Node.Js, Express, REST APIs, Postgre SQL)AI-native mindset: you reach for agents by default, understand MCP and agentic orchestration patterns, and have built guardrails to trust them progressivelyStrong UX instincts you can distinguish good from bad UX and share examples to back it upSelf-driven and business-aware: you care about solving real problems and moving the needle on metrics, not just shipping featuresNice to HaveHands on experience with LLMs in production, prompt tuning, RAG pipelines, or vector databases (Pinecone, Weaviate)Familiarity with agentic frameworks (Lang Graph, Crew AI) and LLM observability tools (Langfuse, Lang Smith)Experience with GCP and cloud platformsA genuine passion for staying on the frontier: new models, protocols (MCP, A2 A), and developer tooling