> For the complete documentation index, see [llms.txt](/llms.txt).

# Use environment variables

You can use environment variables to compile your Snap. This is useful if you want to use different variables for testing your Snap locally and publishing your Snap. You can use environment variables [on the command line](#use-environment-variables-on-the-command-line)or [in a .env file](#use-environment-variables-in-a-env-file).

note

In addition to the environment variables you set, the following environment variables are set by the Snaps CLI:

- `NODE_ENV="production"`
- `NODE_DEBUG=false`
- `DEBUG=false`

## Use environment variables on the command line

1. Specify environment variables on the command line. For example:  
```bash  
PUBLIC_KEY=abc123 SNAP_ENV=dev  
```
2. Build your Snap using the [Snaps CLI](/snaps/reference/cli/):  
```bash  
yarn mm-snap build  
```

## Use environment variables in a `.env` file

1. Specify environment variables in a `.env` file. For example:  
.env  
```text  
PUBLIC_KEY=abc123  
SNAP_ENV=dev  
```
2. Specify the environment variables in your Snap's [configuration file](/snaps/learn/about-snaps/files/#configuration-file) using the `environment` option. For example:

**JavaScript**  
snap.config.js  
```javascript  
require('dotenv').config()  
module.exports = {  
  environment: {  
    SNAP_ENV: process.env.SNAP_ENV,  
    PUBLIC_KEY: process.env.PUBLIC_KEY,  
  },  
  // Other options.  
}  
```

**TypeScript**  
snap.config.ts  
```typescript  
import type { SnapConfig } from '@metamask/snaps-cli'  
import * as dotenv from 'dotenv'  
dotenv.config()  
const config: SnapConfig = {  
  environment: {  
    SNAP_ENV: process.env.SNAP_ENV,  
    PUBLIC_KEY: process.env.PUBLIC_KEY,  
  },  
  // Other options.  
}  
export default config  
```
3. You can also use environment variables directly in your Snap. For example:

**JSX**  
index.tsx  
```tsx  
import { Box, Text, Heading } from '@metamask/snaps-sdk/jsx'  
await snap.request({  
  method: 'snap_dialog',  
  params: {  
    type: 'alert',  
    content: (  
      <Box>  
        <Heading>This custom alert is just for display purposes.</Heading>  
        <Text>  
          SNAP_ENV is {process.env.SNAP_ENV}, PUBLIC_KEY is {process.env.PUBLIC_KEY}  
        </Text>  
      </Box>  
    ),  
  },  
})  
```

**Functions**  
index.ts  
```typescript  
import { panel, text, heading } from '@metamask/snaps-sdk'  
await snap.request({  
  method: 'snap_dialog',  
  params: {  
    type: 'alert',  
    content: panel([  
      heading('This custom alert is just for display purposes.'),  
      text(`SNAP_ENV is ${process.env.SNAP_ENV}, PUBLIC_KEY is ${process.env.PUBLIC_KEY}`),  
    ]),  
  },  
})  
```