Fullstack IA Developer (.NET/ React)

Responsibilities

• Design and build the validation interface in React and TypeScript: document upload, tender classification review, budget comparison views and deviation dashboards.
• Implement data-dense views presenting budget line items and statistical baselines (mean, median, deviation by work type, size and location), with drill-down from summary to individual line item.
• Build the human-in-the-loop approval workflow: review, annotate, override and approve AI-generated results, with full traceability of who changed what and why.
• Surface AI provenance in the interface — show the source document and passage supporting each generated figure so users can verify output rather than trust it blindly.
• Implement responsive, accessible UI consistent with client branding; deliver interfaces in Spanish with an internationalisation-ready structure.
• Handle streaming responses and long-running agent executions with appropriate progress, cancellation and error states.
• Build and maintain backend services and REST APIs in .NET / C# that mediate between the front end and the AI orchestration layer.
• Implement authentication and authorisation, including role-based access control appropriate to confidential supplier pricing data.
• Develop data access and business services against PostgreSQL, and integrate with object storage for source documents.
• Integrate with the agent and MCP layer developed by the Senior AI Engineer, including asynchronous job handling and result persistence.
• Containerise front-end and backend services so they deploy unchanged to cloud, DXC platform or client on-premise infrastructure.
• Contribute to CI/CD pipelines, automated testing (unit, integration, end-to-end) and code review.
• Participate in client demonstrations and gather usability feedback from the teams who will use the tool daily.
• Produce user-facing documentation and support end-user onboarding during pilot and production rollout.

Skills

Must have

• 5+ years of professional full stack development experience delivering production web applications.
• Strong React and TypeScript: modern hooks patterns, state management, component architecture and performance optimisation.
• Proven experience with data-dense interfaces: complex tables, filtering, sorting, drill-down navigation and data visualisation (AG Grid, TanStack Table, Recharts, D3 or equivalent).
• Backend development in .NET / C#: ASP.NET Core, REST API design, Entity Framework Core, dependency injection and asynchronous programming.
• Relational database skills: SQL, schema design and query optimisation. PostgreSQL preferred.
• REST API integration, including asynchronous and long-running operations, streaming responses and robust error handling.
• Docker and container-based delivery; ability to build applications that deploy to cloud or on-premise environments without provider-specific rework.

  Mandatory given the open deployment decision.

• Authentication and authorisation: OAuth2/OIDC, JWT, role-based access control.

  Microsoft

  Entra ID experience valued.

• Git-based workflows, code review discipline and CI/CD familiarity.
• Automated testing across front-end and backend (Jest, Vitest, Playwright or Cypress; xUnit or NUnit).
• Spanish C1/Native and English B2 or above. (technical reading)

Nice to have

• Experience building interfaces for AI or LLM-powered applications: chat and streaming UIs, citation and source display, confidence indicators, feedback capture.
• Azure platform experience: App Service, Container Apps, AKS, Blob Storage, Key Vault, Entra ID.
• Kubernetes and Helm for portable deployment across cloud and on-premise targets.
• UX sensibility for analytical and decision-support tools; ability to prototype and iterate with end users.
• Accessibility standards (WCAG) and internationalisation frameworks (i18next or equivalent).
• Python familiarity, sufficient to read and integrate with the AI services built by the Senior AI Engineer.
• Reporting and export capability: PDF and Excel generation for budget and deviation reports.
• Domain exposure to procurement, tendering, construction cost control, ERP or utilities systems.
• Certifications: Microsoft Certified Azure Developer Associate (AZ-204) or equivalent.