rsnext/errors/promise-in-next-config.mdx

---
title: Promise In Next Config
---

## Why This Error Occurred

The webpack function in `next.config.js` returned a promise which is not supported in Next.js. For example, below is not supported:

```js filename="next.config.js"
module.exports = {
  webpack: async function (config) {
    return config
  },
}
```

## Possible Ways to Fix It

In Next.js versions above `12.0.10`, `module.exports = async () =>` is supported.

For older versions, you can check your `next.config.js` for `async` or `return Promise`.

Potentially a plugin is returning a `Promise` from the webpack function.