What does Heap Usage mean in PM2

Question

What does Heap Usage mean in the "Custom Metrics" window when running pm2 monit?

The value for my server gets dangerously close to 100%.

Answer 1

The heap is a memory used by programming languages to store global variables. By default, all global variable are stored in heap memory space.

It`is maybe because of your programs variable.

you can reset it after it exceeded the limit or force pm2 do it for you automatically.

pm2 start api.js --max-memory-restart 300M