Job Description
You will work on the development, maintenance , support and incremental modernisation of the UK Interactive systems (known as UKI). The role is hands-on and delivery-focused , supporting agreed enhancements, defect fixes, production support, security remediation, performance improvements and ongoing de-risking activity across existing UKI web-based applications.
The UKI systems are live, customer-facing platforms used by business users, suppliers and external customers. The role therefore requires a developer who is comfortable working with existing legacy applications, particularly WebForms and SQL Server-based systems , while also supporting gradual modernisation using newer, supported technologies where appropriate.
The role will work closely with technical leads, existing developers, support team and business stakeholders to ensure the systems remain stable, secure, maintainable and fit for purpose for current customers.
Responsibilities
Develop and maintain UKI web applications ( / WebForms) Deliver enhancements, bug fixes,



and performance improvements Support live production systems and troubleshoot issues end-to-end Work with SQL Server (queries, views, stored procedures, data analysis) Contribute to modernization of legacy components (.NET / Azure) Improve application performance, security, and reliability Support integrations, background jobs, and data processes (imports/exports) Assist with security fixes and remediation on existing systems Collaborate with developers, tech leads, and support teams
Qualifications
Strong experience with .NET technologies , particularly / WebForms Solid experience with SQL Server (queries, views, stored procedures, data analysis) Frontend basics: JavaScript, HTML, CSS (jQuery is a plus) Experience working on legacy systems and existing codebases Comfortable supporting live, customer-facing applications Nice to Have
C# / modern .NET Azure (App Services, SQL, DevOps) Web APIs Experience with system modernizatio

📌 .NET Developer (Madrid)
🏢 SGS
📍 Madrid