article title with env variable linked to HTTP verbs

Access environment variables in your templates

Learn how to access environment variables in your mock server templates to avoid exposing your API keys.

In this tutorial, we will learn how to access environment variables in your mock server routes using the getEnvVar templating helper. It allows you to avoid exposing your API keys and other sensitive parameters in your mock server configuration and to easily manage your configuration across different environments.

 Scope and support

Environment variables are available everywhere templating helpers are supported: response body, rules, etc.

They are available in all your environments, in the desktop application, or when using the CLI or the serverless library.

 1. Access environment variables

To access an environment variable in your templates, use the getEnvVar helper. By default, only the environment variables prefixed with MOCKOON_ are available. You can access the variable in your templates using the getEnvVar helper with or without the prefix. If you omit the prefix, the helper will automatically add it:

{{getEnvVar 'MOCKOON_MY_VARIABLE'}} {{getEnvVar 'MY_VARIABLE'}}

 2. Change the prefix

You can change the prefix or remove it entirely in the desktop application settings:

desktop application settings showing the prefix input

You can also modify the prefix when running your mock with the CLI by using the --env-vars-prefix flag:

mockoon-cli start --env-vars-prefix MY_PREFIX_ --data ./mock.json

Finally, the prefix can also be changed when using the serverless library by using the envVarsPrefix option:

const mockoonServerless = new mockoon.MockoonServerless(mockEnv, { envVarsPrefix: 'MY_PREFIX_' });

 3. An example use case: authentication token

Let's say you need Mockoon to forward some calls to a third-party API using the proxy mode. This API requires an authentication token, and you don't want to store it in your mock server configuration.

You can store this token in an environment variable and access it in Mockoon using the helper.

 Create an environment variable

In your terminal, set the environment variable:

export MOCKOON_API_TOKEN=abcd1234

 Access the environment variable and send it to the third party API

In your mock server, we will enable the proxy mode, point to the correct API endpoint (here, the endpoint is a fictive one), and use the getEnvVar helper to access the token and add it to an Authorization header:

view of Mockoon proxy settings showing an url and an authorization header

You can see that we are using the getEnvVar helper to access the MOCKOON_API_TOKEN environment variable and add it to the Authorization header:

Bearer {{getEnvVar 'MOCKOON_API_TOKEN'}}

Now, when you send a request to a non-existing route, for example, GET http://localhost:3002/users, Mockoon will forward it to the third-party API with the correct Authorization header.

To simulate this, we will point the proxy to another Mockoon instance running on http://localhost:3001 instead of

view of Mockoon proxy settings showing an url and an authorization header

After making a call to our original mock server running on http://localhost:3002, we can inspect the forwarded request in the other instance and verify that the Authorization header is correctly set:

view of the forwarded request showing the authorization header