Worked on the grafana/mimir repository to deliver a comprehensive upgrade of Grafana Alerting dependencies and a refactor of the Alertmanager component. The project involved backend development in Go, focusing on API integration and dependency management. The Alertmanager was enhanced to use a URL-based image provider and a new HTTP client for webhook configurations, while deprecated sender functionality was removed to streamline maintenance. Test suites were updated to ensure regression coverage and compatibility with remote image URLs. These changes improved the reliability and scalability of alert rendering, aligning the system with the latest Grafana alerting features and simplifying future development efforts.