Mytaxi, Europe's leading taxi app, leverages the Elastic Stack to maintain app responsiveness and manage extensive logs, supporting a backend of approximately 50 microservices. Initially using a simple Elastic setup, exponential growth necessitated a new logging cluster by mid-2015, addressing increased data storage and performance demands. The new architecture, implemented with AWS and Ansible, features ten nodes of m1.xlarge instances, enabling efficient log storage and retrieval for up to 90 days. This setup supports seamless service migrations, as demonstrated during a significant backend shift to Docker containers on AWS ECS, monitored closely using Kibana for real-time service performance. The Elastic Stack not only provides a comprehensive system overview but also empowers developers to analyze bugs and assess changes' impacts, aligning with the company's goal to enhance the taxi experience across Europe.