Senior Full-Stack Engineer (TypeScript)
Department: ENGINEERING
Location: Madrid
Employment Type: FullTime
You'll build the surfaces through which humans interact with our agents — dashboards, approval flows, real-time visualizations, and the counterparty portal that pulls new companies into the network.
What you'll do
Chat & real-time architecture — WebSocket-based event streaming, agent notification routing, dynamic query handling.
Cash forecast visualization — Probabilistic forecasts with uncertainty bands and drill-down into underlying invoices and assumptions.
Counterparty portal — A lightweight portal where suppliers and customers can see invoice status, disputes, and payment promises via secure magic links.
Approval UI — The human-in-the-loop interface where agent reasoning and source documents are reviewed before actions are approved.
Authentication & session management — OAuth 2.0 / OIDC integration, JWT with tenant context, session lifecycle (Redis-backed), magic link token issuance for the counterparty portal.
API / BFF (Backend-for-Frontend) layer — The TypeScript service layer that mediates between the React frontend and the Python agent backend. REST, GraphQL, and WebSocket endpoints with tenant-scoped security.
MCP server — A Model Context Protocol endpoint for external AI agent integration, enabling agent-to-agent interoperability across the supply chain.
What we're looking for
5+ years architecting TypeScript/React applications in production.
Systems design instincts — you think in components, contracts, data flows, and failure modes.
Deep experience with real-time architectures (WebSockets, event-driven frontends).
Experience designing data visualization systems and API layers for multi-tenant SaaS.
Strong understanding of frontend security (CSP, CSRF, session management, input sanitization).
Effective use of AI coding tools with strong code review skills for security-sensitive output.
Strong product sense. You have opinions, you back them with data and gut, and you speak up.
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