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.
Timber.io - Timber.io is the best logging platform for ruby, node, elixir and much more.
Raygun - Raygun gives developers meaningful insights into problems affecting their applications. Discover issues - Understand the problem - Fix things faster.
PublicAPIs - Explore the largest API directory in the galaxy
RabbitMQ - RabbitMQ is an open source message broker software.
API List - A collective list of APIs. Build something.