Overview
Both are excellent. The choice is usually about team familiarity and the shape of the workload, not raw speed.
Node.js
Great for I/O-heavy APIs, shares types with the frontend, and is fast to build with. Single-threaded, so offload CPU work to workers.
Go
Excellent for concurrent, CPU-bound services and CLIs. Compiles to a single binary and scales well, but the ecosystem is smaller than Node's.
How to decide
If your team is TypeScript-first and the work is I/O-bound, Node. If you need many concurrent connections with low latency and CPU work, consider Go.