The docs make it very easy to deploy on Northflank. You just need to make sure your env variables contain NPM_CONFIG_FORCE=true to ensure npm i --force is run to install your dependencies.
If you're deploying on Railway.app, chances are you'll run into issues at install step. To ensure Nixpacks actually installs dependencies, you'll need to create a new file at root called nixpacks.toml with the following content:
[phases.install]
nixCmds = ['npm','install','--force']
This ensures it force installs all npm packages.
Ensure your config variables have an entry for NPM_CONFIG_FORCE=true to force install packages.