Prometheus - An open-source systems monitoring and alerting toolkit.
Raygun - Raygun gives developers meaningful insights into problems affecting their applications. Discover issues - Understand the problem - Fix things faster.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Sentry.io - From error tracking to performance monitoring, developers can see what actually matters, solve quicker, and learn continuously about their applications - from the frontend to the backend.
Fluent Bit - Data collector and log forwarder.
RabbitMQ - RabbitMQ is an open source message broker software.