Qonto, a fintech company focused on simplifying banking processes for SMEs and freelancers, transitioned from using Elasticsearch to Grafana Loki for its network observability platform to manage massive amounts of network logs more cost-effectively. The decision came in response to the high storage costs associated with Elasticsearch, despite its capabilities, and the prohibitive pricing of AWS's native toolchain. Since implementing Loki in January 2023, Qonto has been able to handle 30 TB of compressed data monthly with improved efficiency in searching and filtering logs using Loki’s LogQL. The new architecture leverages AWS resources such as S3 buckets and Lambda functions for log ingestion, with Prometheus and AlertManager used for metrics and alerts. The switch to Loki has facilitated the detection of network traffic issues swiftly, making the task nearly enjoyable for the SRE team, and has prompted further expansion of its application to other AWS services, demonstrating the versatility and effectiveness of open-source solutions in enhancing network reliability and cost management.