We''re looking to engage an experienced Full Stack Developer to deliver a defined package of security and compliance-focused enhancements to our client''s web platform. This is a short-term, well-scoped contract focused on strengthening authentication, auditing, and application security within an existing production system. The Role You will be responsible for implementing several targeted improvements to a live ASP.NET MVC application, including: Adding multi-factor authentication (MFA) to user login Implementing step-up verification for sensitive user actions to confirm user presence at the point of authorisation Enhancing audit logging to capture user actions with timestamps Reducing security vulnerabilities by updating legacy libraries and resolving AppCheck warnings Producing clear technical documentation and handing over to the internal team Tech Stack ASP.NET MVC (.NET Framework 4.8) C# JavaScript, HTML, CSS REST APIs Required Experience Strong background in authentication and authorisation patterns Experience securing high-risk or regulated user actions (e.g. approvals, authorisations) Comfortable working independently on well-defined enhancements Ability to work within an existing codebase and platform constraints Clear documentation and handover skills Desirable Experience in regulated environments Familiarity with step-up authentication or electronic signature workflows Pragmatic approach to improving security without large-scale rewrites For more in