Raygun - Raygun gives developers meaningful insights into problems affecting their applications. Discover issues - Understand the problem - Fix things faster.
draw.io - Online diagramming application
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.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
RabbitMQ - RabbitMQ is an open source message broker software.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.