Environment variables

Service environment variables supply values used when Coolify renders the stack's .env file and deployable Compose definition.

Open the Service, then select Configuration > Environment Variables.

Understand the source of a variable

Source	Where to change it
`${VARIABLE}` reference in Compose	Environment Variables
Hard-coded value in a Compose `environment:` entry	Edit Compose File
`SERVICE_URL_`, `SERVICE_FQDN_`, or `SERVICE_NAME_*`	The matching domain or Compose service; Coolify manages these variables.
Generated credential such as `SERVICE_PASSWORD_*`	Environment Variables, unless the field is locked by the template or your role.
Shared-variable reference	The shared-variable scope and the Service variable that references it.

Coolify shows hard-coded Compose values separately and filters generated URL, FQDN, and service-name values from that list.

Add and edit values

Use Normal view to manage one variable at a time. Service variables can be multiline or literal:

enable Is Multiline? for a certificate, private key, or configuration value with line breaks
enable Is Literal? when a $ reference must remain text instead of being expanded

Use Developer view to edit several entries in .env format:

APP_ENV=production
DATABASE_URL=postgresql://app:password@database:5432/app
LOG_LEVEL=info

Saving Developer view creates, updates, and removes managed variables to match the text. Locked secrets and multiline values cannot be changed from Developer view.

Required values and defaults

The Compose expression determines the initial requirement:

Syntax	Coolify behavior
`${VARIABLE}`	Creates an editable value that can be empty.
`${VARIABLE:-default}`	Creates the variable with the fallback as its initial value.
`${VARIABLE:?}`	Marks the variable as required and blocks deployment while it is empty.

For example:

services:
  app:
    environment:
      APP_SECRET: ${APP_SECRET:?}
      LOG_LEVEL: ${LOG_LEVEL:-info}

After saving the Compose definition, enter APP_SECRET before deploying.

Reuse values across components

Reference one variable from every component that needs it:

services:
  api:
    environment:
      DATABASE_URL: ${DATABASE_URL:?}
  worker:
    environment:
      DATABASE_URL: ${DATABASE_URL:?}

Coolify stores one DATABASE_URL value for the Service and writes it into the .env file used by Docker Compose.

Use a shared variable when several Coolify resources need the same value:

DATABASE_URL={{environment.DATABASE_URL}}

Read Shared variables for team, project, environment, and server scopes.

Generated domains and credentials

Variables that start with SERVICE_ can instruct Coolify to generate a value. URL and FQDN variables are tied to the matching Compose service and its domain configuration. Password, username, and random-value variables persist with the Service so components can share them.

Read Docker Compose generated Service values before renaming or deleting one. Coolify prevents deleting a managed variable while the Compose definition still uses it; remove the reference from Compose first.

Apply and verify changes

Save the variable.
Confirm every required value is filled.
Restart or deploy the Service so Coolify rewrites .env and recreates the containers.
Inspect the deployment output and component logs.
Verify the behavior that consumes the value.

Do not paste production secrets into support messages or screenshots. Team members can have restricted access to secret values even when they can view the Service.