Worked on the guardian/csnx repository to deliver mobile-first newsletter capabilities by implementing support for mobile banner URLs in newsletter types. Extended the existing data model using TypeScript to introduce a new field that enables mobile-optimized banner rendering, allowing for more flexible and targeted campaign delivery. Focused on API development to ensure seamless integration of the new feature, which lays the groundwork for enhanced content rendering on mobile devices. The technical approach prioritized future scalability and reduced integration effort, enabling faster rollout of mobile features. No bugs were addressed during this period, with efforts concentrated on feature development and technical readiness.