Software Developer (React / .NET Core) Duration: 12 Months Workload: Full Time Hours Setup: Freelance (Daily Rate / Limited Company / Umbrella / Sole Trader) Location: Barcelona, Spain (hybrid)

We are looking for a hands-on Software Developer to support the modernisation of a business-critical legacy platform into a scalable, API-first architecture using React and .NET Core technologies.

Key Responsibilities Build and enhance ASP.NET Core Web APIs. Develop modern React SPA components and integrate them with backend services. Support the migration of legacy Web Forms functionality into reusable API-driven solutions. Work with SQL Server, business logic layers, validation and error handling. Contribute to testing, debugging and overall application quality.



Support CI/CD processes and collaborate closely with architects and development teams in an Agile environment.

Must-Have Skills 3+ years of software development experience. Strong C# and ASP.NET Core Web API expertise. Strong React and JavaScript development experience. Experience with REST APIs and SQL databases. Strong communication skills and ability to work independently. Fluent English and Spanish.

Nice-to-Have Experience with Web Forms or other legacy systems. AWS exposure (S3, API Gateway, Lambda). JWT/OIDC authentication experience. CI/CD knowledge.

📌 Software Engineer (React /.NET Core) (Barcelona)
🏢 Airswift
📍 Barcelona