Sentry Software, a small company focused on sustainability, has successfully reduced its carbon emissions by 7% year over year through innovative use of open-source technologies and open standards. By developing a monitoring system using Grafana dashboards and OpenTelemetry guidelines, they efficiently tracked and reduced electricity usage at their primary data center in Paris, achieving a 19% reduction in AC energy consumption. The company re-engineered its proprietary Hardware Sentry tool as a Prometheus exporter and utilized custom scripts to gather detailed data on energy consumption and carbon emissions. This allowed them to make informed decisions, such as gradually increasing the data center's temperature to 27 degrees Celsius, resulting in significant energy savings. Sentry Software's approach demonstrates how open-source solutions can empower organizations to effectively monitor and reduce their IT infrastructure's carbon footprint, offering their tools for free to encourage others to follow suit in the journey toward carbon neutrality.