How do I build and deploy a pure lambda server on Netlify?

I’m splitting a project into a 1) lambda functions server; 2) web client that calls those functions.

I can successfully run server and client using netlify dev from my localhost (port 8881 for the server, 8888 for the client). They talk to each other and everything is hunky-dory.

Not so when I try to netlify build the server, though, it fails. I’m not even sure why it works with netlify dev TBH. The command I’m using for the dev build is:

BROWSER=none;  -p 8881

But netlify build is configured by .toml file, which I currently have as:

  command = "build"
  publish = "build"
  build = "esbuild"

  directory = "netlify/functions"
  node_bundler = "esbuild"
  external_node_modules = ["express", "import-fresh"]

But there is no ‘build’ command, so I get a 127 error. Note that It originally was `react-scripts build’ (and still lis for the client), but I’m not serving a page, just lambda functions (react-scripts might still work if I add an index.html to the project, but that seems like a hack).

Back to the original question: I wan’t to deploy (only) lambda functions from a server, but I don’t know what the configuration should be for build/deploy. Can you help me?

Nevermind, I found this post and turns out I don’t need a build command, but I still need a stub html page (apparently).

I’m close to getting it working now, I just need to set up environment variables on the netlify project.