Environment variables

Use environment variables in BrowserStack Load Testing to parameterize tests and avoid hard-coding secrets. You can also mask sensitive values to prevent exposure in the browser console or CLI logs.

You can set environment variables to pass dynamic values to your load tests, such as API keys, user credentials, or configuration settings.

Mask sensitive values

Mark environment variables as masked to hide their values across the BrowserStack Load Testing dashboard. Use this for API keys, passwords, tokens, and other credentials you don’t want surfaced when reviewing or sharing a load test.

Masked values are hidden:

• When configuring a load test
• On load test details and run history pages
• When comparing runs
• In links you share with others

Masked values are not hidden:

• Inside your test runtime - your script reads process.env.X as the original value. This is required for tests to actually run.
• In logs your test prints to stdout - anything your script writes (console.log, framework debug output) appears verbatim in your run logs. If your test logs a secret, mask it in your test code as well.
• In your local .env source file, BrowserStack never modifies the file you upload. Masking is opt-in per variable. Both UI Builder and CLI support it - see each tab below for the exact steps.

Configure environment variables

First, set up your environment variables using either the UI Builder or CLI. Once configured, you can enable masking for sensitive values.

Depending on your preferred method, select any one of the following:

${__P(target_host, localhost)}
${__P(api_key, default-key)}

env:
  sources:
   - path/to/env/file
  variables:
   - name: "variable1"
     value: "value1"
   - name: "variable2"
     value: "value2"

env:
  variables:
   - name: "API_KEY"
     value: "sk-prod-abc123xyz"
     isMasked: true
   - name: "PUBLIC_URL"
     value: "https://api.example.com"

Parameterize with JMeter properties

If you’re using Apache JMeter, you can parameterize your scripts using the JMeter __P() function. The __P() function resolves property values from the environment variables you configure in BrowserStack Load Testing.

Values from both file uploads and manually added key-value pairs feed into JMeter’s property table. When your script references a property using ${__P(name, default)}, the runner injects the value you specified, or uses the default if not supplied.

How JMeter properties work

In your JMeter script, use the __P() syntax to reference a parameter:

${__P(target_host, localhost)}
${__P(api_key, default-key)}
${__P(request.timeout, 5000)}

When the test runs on BrowserStack Load Testing:

1. The runner parses your Env Variables (files and grid).
2. Each key from your environment variables is injected into JMeter’s property table.
3. At test time, ${__P(name, default)} resolves to:
   • The value you supplied through environment variables.
   • The default value specified in your script if no value is configured.

Example

In your JMeter script (HTTP Request sampler):

• Server Name: ${__P(target_host, localhost)}
• Path: /api/users

In BrowserStack Load Testing, configure an environment variable:

• Key: target_host
• Value: api.example.com

When the test runs, the HTTP request uses api.example.com as the server name.

Related topics

• Configure load parameters - Overview of all available load configuration options
• Per-VU external inputs with test data - Pass dynamic data files to your load tests