Some feedback:

• for public URLs use https://${{RAILWAY_PUBLIC_DOMAIN}} or https://${{service name.RAILWAY_PUBLIC_DOMAIN}}
• for private URLs use http://${{service name.RAILWAY_PRIVATE_DOMAIN}}:port
• for secrets use ${{secret(32)}}

Documatiton references:

https://docs.railway.app/reference/variables#railway-provided-variables

https://docs.railway.app/guides/create#template-variable-functions