KPI Reporter is a dev-friendly, on-premises tool for for crafting automated reports.
Support for a variety of reporting sources is built-in, including, e.g., MySQL databases, Prometheus metrics, and the Jenkins API. Reports can be sent via email (with plugins for SMTP and SendGrid), Slack, or simply rendered as HTML.
Author note: I created this tool after being surprised that there was a distinct lack of simple developer-friendly reporting tools for communicating business and/or operational KPIs. I hope you find it useful as well. For more information, see Motivation.