Guide for fullstack developers on effective log management: outlines challenges (scalability, noisy data, real-time needs, centralization), explains how ELK (Elasticsearch, Logstash, Kibana) enables scalable, flexible, real-time analysis, compares alternatives (Splunk, Graylog, Fluentd), gives selection criteria (scalability, integration, customization, cost), and showcases e-commerce analytics and real-time security monitoring use cases.