Hi @Urs_Boller , the .env file is to defined the environment variables at build time. If you want to use them in the actions, you need to pass those variables to the actions via default parameters. To do the mapping, in manifest.yml, for each action there is an "inputs" section. You could simply map all the variables you want for the action there. For example: in .env you have `CAMPAIGN_TENANT="my-tenant"`, then in manifest add `campaignTenant: $CAMPAIGN_TENANT` to the respective action, finally in the action get it with `const tenant = params.campaignTenant`.
Reference docs: https://github.com/AdobeDocs/project-firefly/blob/master/getting_started/first_app.md#5-anatomy-of-a...