This project provides a sample setup of two Spring Boot 3.x applications that use Spring Boot 3's new observability features in combination with OpenTelemetry. Since Spring Boot 3 observability only covers exposure of metrics and traces using OTLP, but not logs, this project also shows how to easily code a custom Logback Appender to intercept logs and export them as OTLP traffic. This appender is inspired by OpenTelemetry's Logback Appender and reuses some of its code, yet removes the lifecycle issues that it comes with.