> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fly.io/llms.txt
> Use this file to discover all available pages before exploring further.

# PHP and Node Versions

Your app is a special snowflake. Here are a few things you may want to customize further!

## Node and PHP Version

We try to detect your local version of PHP and match it (with a minimum of PHP 7.4). If we can't determine the version, we default to version 8.2.

For NodeJS, we default to version 18.

You can define the PHP and NodeJS versions you want by adding/adjusting build arguments in the `fly.toml` file:

```toml theme={null}
[build]
  [build.args]
    PHP_VERSION = "8.3"
    NODE_VERSION = "18"
```

Alternatively, you can set (or over-ride) the build arguments when deploying:

```bash theme={null}
fly deploy --build-arg "PHP_VERSION=8.1" --build-arg "NODE_VERSION=14"
```