See the README for each service in GitHub - /flowmazonbackend/README.md and /flowmazonfrontend/README.md- for:

• a list of required and optional configuration keys for each service, and
• the mechanisms through which values may be provided for these - e.g. using config files in local development but environment variables at build and/or run of deployment or containers

For actual sources of the values of these keys in a specific environment, see the definition of that environment:

Local Environments

Non-local Environments