Full Stack Development Consultant (Mobile, Web, and Integration)

About the role

We are looking for an experienced independent consultant to design, build, test, and hand over a production‑ready cross‑platform mobile app, companion web app, and shared backend. The solution must integrate with DHIS2 and provide single sign‑on via Keycloak.

Key responsibilities

• Design and develop a single‑codebase mobile application for Android and iOS with offline‑first data capture and background synchronization.
• Create a responsive web application that shares domain logic and design system with the mobile app.
• Build and maintain backend services in C# (.NET) and Python, exposing versioned REST APIs (OpenAPI).
• Integrate the platform with an external DHIS2 instance, handling metadata alignment, data flows, and robust synchronization.
• Implement SSO across mobile, web, and backend using Keycloak, configuring realms, clients, scopes, and OIDC/OAuth2 flows (including PKCE).
• Address non‑functional requirements such as performance, low‑end device optimisation, security, and monitoring.

Required profile

• Proven experience delivering full‑stack solutions on a contract basis.
• Ability to work full‑time on‑site for a 12‑week fixed‑term engagement.
• Self‑managed responsibility for deliverables, tax and statutory obligations.

Required skills

• C# and .NET
• Python
• REST API design (OpenAPI)
• Cross‑platform mobile development (offline‑first, background sync, conflict resolution)
• DHIS2 Web API integration
• Keycloak, OIDC, OAuth 2.0, PKCE
• Responsive web development with role‑based access control
• Relational databases, migrations, indexing, query performance optimisation
• Versioning, staged rollout, crash and performance monitoring