System environment variables

System environment variables are local environment variables that can change Wrangler's behavior. There are three ways to set system environment variables:

Create an .env file in your project directory. Set the values of your environment variables in your .env file. This is the recommended way to set these variables, as it persists the values between Wrangler sessions.
Inline the values in your Wrangler command. For example, WRANGLER_LOG="debug" npx wrangler deploy will set the value of WRANGLER_LOG to "debug" for this execution of the command.
Set the values in your shell environment. For example, if you are using Z shell, adding export CLOUDFLARE_API_TOKEN=... to your ~/.zshrc file will set this token as part of your shell configuration.

Note

During local development, the values in .env files are also loaded into the env object in your Worker, so you can access them in your Worker code.

For example, if you set API_HOST="localhost:3000" in your .env file, you can access it in your Worker like this:

const apiHost = env.API_HOST;

See the Environment variables and secrets page for more information on how to use .env files in local development.

Supported environment variables

Wrangler supports the following environment variables:

CLOUDFLARE_ACCOUNT_ID stringoptional
- The