1. Designed and built a distributed uptime monitoring system that performs scheduled health checks (HTTP/HTTPS) for multiple endpoints, persisting latency, status codes, and failure reasons, and supporting time-series aggregation. 2. Built a scalable data retention and rollup pipeline, using TTL indexes and scheduled jobs to automatically expire raw check data and generate daily aggregated statistics, optimizing storage usage for historical insights. 3.Implemented role-based access control (RBAC) with fine-grained permissions (captain, member), enforcing authorization at API and data layers to prevent cross-tenant data access and ensure least privilege security.