Environment Variables

You can set and use your own environment variables in your projects. They will be available in your code via Node.js’ process.env property.

These are typically used for setting your deployment context and private API keys. This is also the approach used to enable DEBUG mode.

Setting your own Jump to heading #

Via .env file Jump to heading #

For private keys and other sensitive information, you’ll want to create a .env file and use the dotenv package to setup those values.

Via the command line Jump to heading #

Mac OS (or Linux, etc) Jump to heading #

MY_ENVIRONMENT=production npx @11ty/eleventy

Windows cmd.exe Jump to heading #

set MY_ENVIRONMENT=production & npx @11ty/eleventy

Windows Powershell (VS Code default) Jump to heading #

$env:MY_ENVIRONMENT="production"; npx @11ty/eleventy

Via an npm script Jump to heading #

You can also use the above commands in an npm script in your project’s package.json file.

{
  "scripts": {
    "build:prod": "MY_ENVIRONMENT=production npx @11ty/eleventy"
  }
}

Use Case Ideas Jump to heading #

• Expose Environment Variables to your templates using JavaScript Data Files.
• Opt-in to git Last Modified only in production
• Only perform Eleventy Serverless plugin copy (via copyEnabled) in production
• Use fewer image formats in the Image plugin to speed up local development

Eleventy Supplied Added in v1.0.0 Jump to heading #

Node.js exposes environment variables under process.env.

Eleventy also supplies its own Eleventy-specific environment variables, usually intended for more advanced use cases. You can use these in your configuration or in data files as needed.

• process.env.ELEVENTY_ROOT the absolute path to the directory in which you’ve run the Eleventy command.
• process.env.ELEVENTY_SOURCE is the method in which Eleventy has run, current either cli or script.
• process.env.ELEVENTY_SERVERLESS is set to true (String) if Eleventy is running in serverless mode. If Eleventy is not running in serverless mode—due to Node forcing environment variables to be strings—this variable will not exist.
• process.env.ELEVENTY_RUN_MODE Added in v2.0.0-beta.2 is one of build, serve, or watch.

Other pages in Using Data:

• Configure your Templates
• Eleventy Supplied Data
• Data Cascade
  • Front Matter Data
    • Custom Front Matter
  • Template & Directory Data Files
  • Global Data Files
    • Data Preprocessing
  • Data Deep Merge
  • Config Global Data
  • Computed Data
• Environment Variables
• JavaScript Data Files
• Custom Data File Formats