Variables

Variables are the environment variables your service starts with: settings, API keys, your database's URL. Each service has its own, and a variable can point at another service's, so your app always gets the database of the environment it runs in.

Add a variable

1. Open your service and go to the Variables tab.
2. Click New Variable, and enter a Key and a Value.
3. Leave Sealed ticked for a secret: you can't read it back or unseal it. Untick it for a value you want to see, or one that holds a reference. Click Add.
4. Click Deploy.

To change or remove a variable, open the menu at the end of its row.

Your running service keeps its old values until you deploy. Changing a variable rebuilds a service built from GitHub on that deploy.

Paste many at once

Click Raw editor to see the service's variables as a .env file (ENV) or as JSON. Paste or edit them, then click Update variables.

• Deleting a line deletes that variable.
• Sealed variables aren't shown and stay as they are.
• Values you save here are plain text. Seal secrets afterwards from their menu.

Seal a secret

A sealed variable is encrypted when you save it, and the dashboard never shows its value again. Your service still gets the real value when it deploys.

• New variables are sealed unless you untick Sealed.
• To seal a plain variable, choose Seal from its menu. You can't unseal it.
• To change a sealed value, delete the variable and add it again.
• A sealed value is stored exactly as typed, so it can't hold a reference.

Reference another service's variable

A reference fills a variable with another variable's value. Write ${{ SERVICE.KEY }} for another service's variable and ${{ KEY }} for one of this service's own:

DATABASE_URL=${{ postgres.DATABASE_URL }}
WEB_URL=http://${{ web.PLOYZ_PRIVATE_DOMAIN }}:8080

Untick Sealed, then type ${{ in the value. The dashboard suggests this service's variables, the variables Ployz provides, and other services' exported variables. Tick Exported on a variable to add it to the suggestions; you can type a reference to any variable either way.

• A reference reads the service of that name in the same environment. In staging, ${{ postgres.DATABASE_URL }} is staging's database.
• A reference to a sealed variable keeps the secret hidden. Your service gets the real value.
• A service that references another starts after it on every deploy.
• Ployz refuses a reference to a service or variable that doesn't exist, and won't delete one that something references. Remove the reference first.
• Write $${{ for a literal ${{.

Variables Ployz provides

Variable	Value
PORT	8080, unless you set it. Your domains and health check reach your app on this port.
PLOYZ_PRIVATE_DOMAIN	The service's private address, like web.internal
PLOYZ_SERVICE_NAME	The service's private name, like web
PLOYZ_ENVIRONMENT_NAME	The environment's name, like production
PLOYZ_SERVICE_ID, PLOYZ_ENVIRONMENT_ID	The service's and the environment's IDs

Only PORT reaches your app on its own. To read another one, reference it in a variable of your own, like SELF_HOST=${{ PLOYZ_PRIVATE_DOMAIN }}. The Variables tab lists them, with their values, under your own variables.

Good to know

• Builds see your variables, sealed ones included. A Dockerfile can keep what it reads in the image, so don't pass long-lived secrets to it as ARGs. See Use variables at build time.
• Branches copy variables. A separate copy of a service in a branch starts with its parent's variables, sealed values included, and changing them leaves the parent alone. A reference to a service the branch shares with its parent reads the parent's values.

Next: add a database.