1. Architecture: The main difference between Hydra Framework and Node.js lies in their architecture. Hydra is a distributed computing framework that simplifies building distributed applications, while Node.js is a runtime environment that allows you to run JavaScript on the server side. Hydra provides a more structured approach to building microservices and managing distributed systems, whereas Node.js is more focused on providing a runtime for executing JavaScript code.

2. Scalability: Another key difference is in terms of scalability. Hydra Framework is designed to easily scale out by adding more nodes to the cluster, making it suitable for large-scale applications. On the other hand, Node.js can also be scaled horizontally, but it may require more effort and manual configuration compared to Hydra.

3. Middleware Support: Hydra Framework comes with built-in middleware support, making it easier to add functionalities such as logging, authentication, and error handling to your applications. Node.js, while offering various modules and libraries for middleware, requires more manual configuration and setup for integrating middleware functionalities.

4. Error Handling: Hydra provides a centralized error handling mechanism, making it easier to manage and trace errors across a distributed system. In contrast, Node.js error handling is more decentralized, often requiring developers to implement their error handling logic within each module or service.

5. Community and Ecosystem: Node.js has a larger community and a broader ecosystem of libraries and frameworks compared to Hydra Framework. This extensive community support for Node.js can be advantageous in terms of finding resources, documentation, and troubleshooting assistance.

6. Use Case: Finally, the use case of each technology differs. Hydra Framework is more suited for building complex, distributed applications that require scalability, fault tolerance, and efficient communication between microservices. On the other hand, Node.js is commonly used for building web servers, API servers, and real-time applications where scalability and performance are key factors, but without the need for a full-fledged distributed system framework.

In Summary, Hydra Framework and Node.js differ in architecture, scalability, middleware support, error handling, community, ecosystem, and use case, each catering to different requirements of building applications.