Since whalerust requires e.g. cargo and wasm-pack I found the easiest way to deploy to vercel is to not deploy automatically upon commit but instead deploy manually:

For that configure vercel to:

• use no build command, install command, deployment command - by setting them to empty

To deploy form you local cli:

• install the vercel cli
• build the whole project in order to populate '/public'
• run vercel/deploy.sh

The .vercel config dir is expected to be located inside this (vercel) folder.