Rolling and blue-green deployments are two key strategies in software engineering designed to minimize downtime and risk during application updates. Rolling deployments gradually update application instances, ensuring continuous availability and allowing for gradual exposure of new features, which is beneficial for applications requiring high uptime but can involve complex version management. Blue-green deployments, on the other hand, maintain two identical environments, enabling instant traffic switchovers and rollback capabilities, thus reducing downtime and risk but at the cost of higher resource consumption. Both strategies aim to enhance the reliability and stability of software services, with each offering distinct advantages depending on project needs, infrastructure, and team workflows. Feature flags can further optimize these approaches by allowing dynamic control over feature releases, enabling zero-downtime deployments, and supporting techniques like A/B testing. Choosing the right deployment strategy involves evaluating user traffic, application architecture, and compatibility with tools like Kubernetes or cloud services, alongside ensuring security, compliance, and a robust CI/CD pipeline.