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Environment Variables

Environment variables are key-value pairs that are stored outside of source code. The values of environment variables can be applied to particular environments in order to change behavior or configuration.

Environment variables can be read into source code and many configuration files in your project. Variables are only applied to environments on new deployments. If you change an environment variable, you must redeploy the environment in order for the updated value to take effect.

Environment variables can be configuration or secrets. While all values are stored encrypted at rest, only non-secret values can be read. Secrets are write-only, meaning the value cannot be retrieved once it is set.

Environment Variable Editor

To set environment variables in your project, open the Settings tab and then select the Environment Variables section.

To create a new variable, click Add new variable.

Enter the name and value of your environment variable and select if you would like the value to be a secret or a regular value.


Environment variables can be applied to one or many different environments. You can select one or more environments in which to apply the variable.

ProdThe environment that is deployed from your default branch in source control. This is usually called main.
PreviewAny environment that is deployed from source control that is not the default branch. (i.e. staging or preview). This also includes any branch that is created from a pull request.
Working CopyAny environment that is deployed while developing with the portal. Each developer gets their own working copy. Working copies are always deployed to

For the Preview environment option, a specific named environment can be selected. For example, if you want a variable set only for the environment deployed from the staging branch in source control.

For the Working Copy option, developers can set a personal override. This value ONLY applies to the developer who set the value.


A single environment variable name cannot overlap environments. For example, if you set a variable named MY_VAR and select all the environments a second variable named MY_VAR cannot be set on say the Production environments.

Reserved Environment Variables

Environment variables cannot start with ZUPLO or __ZUPLO.

Using Environment Variables

There are several places in Zuplo you can access environment variables.


Variables can be accessed in code by importing @zuplo/runtime.

import { environment } from "@zuplo/runtime";

const myVar = environment.MY_VAR;

Configuration Files

Inside some configuration files, environment variables can be referenced with the pattern $env(MY_VAR).

For example, in the policies.json file, an environment variable could be set on a policy option.

"name": "my-custom-code-inbound-policy",
"policyType": "custom-code-inbound",
"handler": {
"export": "default",
"module": "$import(./modules/YOUR_MODULE)",
"options": {
"config1": "$env(MY_CONFIG_VAR)",
"config2": true

Rewrite & Forwarding Handler

When referencing environment variables inside of the URL Rewrite handler and the URL Forward handler, variables are substituted using Javascript style string interpolation.