Node.js leverages the V8 JavaScript engine, which compiles JavaScript directly into native machine code, allowing for highly efficient and fast code execution. Node.js uses an event-driven, non-blocking I/O model, making it exceptionally efficient and suitable for data-intensive real-time applications that run across distributed devices.
Express.js does not impose any specific way of doing things, which allows choosing the best modules and tools for their particular needs. It supports multiple templating engines, and various routing mechanisms and can integrate with many middleware modules to add functionalities like session management, logging, and security, among others.
Being a lightweight framework that operates atop Node.js, Express.js inherits the high performance of Node.js. Its efficient handling of requests and streamlined nature make applications fast and responsive, suitable for environments where performance is critical.
Building with Express.js means you can access the vast ecosystem of Node.js packages. It is also supported by a large community that contributes tools, middleware, and plugins, enhancing the capabilities of Express.js applications and reducing development time with ready-to-use components.