Does Dotvault work with monorepos?

It does, but there is one thing worth knowing before you buy rather than after.

A project in Dotvault is a single folder, and the scan is not recursive. It reads .env and anything starting with .env. from the folder you point it at, and nowhere else. So a monorepo with three packages that each keep their own env files is three projects in the sidebar, not one project with everything underneath it.

In practice that is less annoying than it sounds. You can drag each package folder from Finder straight onto the sidebar, they sit next to each other, and you can reorder them into whatever order you actually think in. Search works across every project you have added, so looking for a variable finds it wherever it lives.

What you do not get is a single view across the whole repo. The comparison grid works within a project, so it will show you development against staging against production for one package, but it will not lay two packages side by side. If that is the thing you were hoping for, it is not there yet.