Senior Full Stack Engineer (.NET/React) - 100% Remote

1 Opening
Madrid

Role description

We are looking for the very Top Talent…and we would be delighted if you were to join our team!

More in details, UST is a multinational company based in North America, certified as a Top Employer and Great Place to Work company with over 35.000 employees all over the world and presence in more than 35 countries. We are leaders on digital technology services, and we provide large-scale technologic solutions to big companies.

What we look for?

We re looking for a highly skilled Full Stack Engineer (.NET/React) with strong Azure experience to participate in the design and delivery of modern, scalable applications.

You ll participate in UI architecture decisions, champion engineering best practices (performance, accessibility, security, testing, CI/CD), and collaborate across product, backend, DevOps, and security to ship high-quality experiences at pace.

Main tasks and accountabilities will be:

Architect & build React applications (SPA/SSR/SSG) with TypeScript, modern hooks, and state management patterns.

Integrate with Azure services: authentication/authorization (Microsoft Entra ID / Okta), hosting (Azure Static Web Apps/Azure App Service), APIs (Azure Functions/APIM), observability (Application Insights/Monitor), secrets (Key Vault)

Accessibility leadership: apply WCAG 2.2 standards, semantic markup, keyboard navigation, focus management, and screen reader support.

Security by design: enforce OWASP recommendations for SPAs (CSP, CSRF/XSRF mitigation, XSS prevention, dependency hygiene), secrets management via Key Vault, and secure OAuth/OIDC flows.

Testing strategy: implement unit testing, component/integration (React Testing Library) with meaningful coverage thresholds and fast CI feedback. DevEx & CI/CD: define pipelines with Azure DevOps or GitHub Actions, set quality gates, PR checks, and trunk.based or GitFlow branching.

What do we expect from you?

5-8+ years building production web apps with React and TypeScript.

Experience as Full Stack Engineer

5 years with .NET

Expertise in React 18+ (hooks, context, suspense patterns) and modern tooling: Vite/webpack, ESLint, Prettier, Babel/ts-config.

Strong state management skills: Redux Toolkit, Zustand, or React Query/TanStack Query; form handling with React Hook Form or Formik.

Azure proficiency in several of: Azure Static Web Apps or App Service for hosting / Azure Functions & API Management for backend integration / Microsoft Entra ID (Azure AD) / B2C for auth (OAuth2/OIDC).

Solid testing skills with Jest, React Testing Library, and Playwright/Cypress.

Experience designing and reviewing CI/CD pipelines (Azure DevOps or GitHub Actions).

English B2+/C1

What can we offer?

23 days of Annual Leave plus the 24th and 31st of December as discretionary days!
Numerous benefits (Health Care Plan, teleworking compensation, Life and Accident Insurances).
Retribución Flexible´ Program: (Meals, Kinder Garden, Transport, online English lessons, Health Care Plan…)
Free access to several training platforms
Professional stability and career plans
UST also, compensates referrals from which you could benefit when you refer professionals.
The option to pick between 12 or 14 payments along the year.
Real Work Life Balance measures (flexibility, WFH or remote work policy, compacted hours during summertime…)
UST Club Platform discounts and gym Access discounts

If you would like to know more, don’t hesitate to apply and we’ll get in touch to fill you in detail. We are waiting for you!

In UST we are committed to equal opportunities in our selection processes and do not discriminate based on race, gender, disability, age, religion, sexual orientation or nationality. We have a special commitment to Disability & Inclusion, so we are interested in hiring people with disability certificate.

Skills
React
.Net
Azure
Remote

About UST
UST is a global digital transformation solutions provider. For more than 20 years, UST has worked side by side with the world’s best companies to make a real impact through transformation. Powered by technology, inspired by people and led by purpose, UST partners with their clients from design to operation. With deep domain expertise and a future-proof philosophy, UST embeds innovation and agility into their clients’ organizations. With over 30,000 employees in 30 countries, UST builds for boundless impact—touching billions of lives in the process.