65 lines
1.8 KiB
Markdown
65 lines
1.8 KiB
Markdown
---
|
|
description: Learn to add and access environment variables in your Next.js application at build time.
|
|
---
|
|
|
|
# Environment Variables
|
|
|
|
> Since the release of Next.js 9.4 we now have a more intuitive and ergonomic experience for [adding environment variables](/docs/basic-features/environment-variables.md). Give it a try!
|
|
|
|
<details>
|
|
<summary><b>Examples</b></summary>
|
|
<ul>
|
|
<li><a href="https://github.com/vercel/next.js/tree/canary/examples/with-env-from-next-config-js">With env</a></li>
|
|
<li><a href="https://github.com/vercel/next.js/tree/canary/examples/with-now-env">With Now env</a></li>
|
|
</ul>
|
|
</details>
|
|
|
|
To add environment variables to the JavaScript bundle, open `next.config.js` and add the `env` config:
|
|
|
|
```js
|
|
module.exports = {
|
|
env: {
|
|
customKey: 'my-value',
|
|
},
|
|
}
|
|
```
|
|
|
|
Now you can access `process.env.customKey` in your code. For example:
|
|
|
|
```jsx
|
|
function Page() {
|
|
return <h1>The value of customKey is: {process.env.customKey}</h1>
|
|
}
|
|
|
|
export default Page
|
|
```
|
|
|
|
Next.js will replace `process.env.customKey` with `'my-value'` at build time. Trying to destructure `process.env` variables won't work due to the nature of webpack [DefinePlugin](https://webpack.js.org/plugins/define-plugin/).
|
|
|
|
For example, the following line:
|
|
|
|
```jsx
|
|
return <h1>The value of customKey is: {process.env.customKey}</h1>
|
|
```
|
|
|
|
Will end up being:
|
|
|
|
```jsx
|
|
return <h1>The value of customKey is: {'my-value'}</h1>
|
|
```
|
|
|
|
## Related
|
|
|
|
<div class="card">
|
|
<a href="/docs/api-reference/next.config.js/introduction.md">
|
|
<b>Introduction to next.config.js:</b>
|
|
<small>Learn more about the configuration file used by Next.js.</small>
|
|
</a>
|
|
</div>
|
|
|
|
<div class="card">
|
|
<a href="/docs/basic-features/environment-variables.md">
|
|
<b>Built-in support for Environment Variables:</b>
|
|
<small>Learn more about the new support for environment variables.</small>
|
|
</a>
|
|
</div>
|