V8 is Google's open-source JavaScript engine written in C++. It compiles JavaScript directly to native machine code before executing it, making it very fast.

Node.js uses V8 to:

• Parse and execute JavaScript code
• Handle memory management and garbage collection
• Provide JavaScript runtime capabilities on the server
• Interface with system-level operations through libuv

V8 features include just-in-time (JIT) compilation, hidden class optimization, and efficient garbage collection.