Senior AI-First Engineers

Builders is an AI-first venture studio in Rotterdam seeking two Senior AI-First Engineers to join their Core Team. The role involves shipping VSI, a multi-agent platform for venture intelligence, from beta to public production, with a focus on engineering velocity and AI-native development.

• Ship VSI to the world — harden core agents, ship company memory v1, ship onboarding flow
• Design and ship multi-tenant architecture across 3-tier RBAC model, Prisma + Supabase data layer
• Own real-time agent orchestration — conversation in → ingest → transcription → agent analysis → living-document updates → UI
• Build API / MCP / CLI surfaces for founders and external agents to plug into VSI
• Ship continuously every week with daily standups and weekly Friday ship days
• Occasionally surface from VSI work to wire up internal automations for the studio

• 5+ years building production platforms (multi-tenant SaaS, AI platforms, data infrastructure, or developer tools)
• AI-native by default — uses Claude Code, Cursor, agent frameworks daily
• Full-stack range — can move between React frontend, Next.js API routes, Vercel background functions, Postgres + pgvector schema design, and AI integration
• AI agent integration experience — LangGraph, LangChain, custom orchestration, RAG pipelines, vector DBs
• Database design rigour — relational + vector, schemas that scale
• Senior judgement — makes architecture calls and owns them
• On-site in Rotterdam — non-negotiable

• Senior salary range — €60–85k base depending on experience
• Equity — meaningful, long-dated, in Builders' STAK structure
• Tool budget — every AI tool, every IDE, every model API