A quick way to get a development environment up and running is with Vagrant. You will need recent versions of [Vagrant](https://www.vagrantup.com/) and [VirtualBox](https://www.virtualbox.org/) installed.
The following command will update your 'hosts' file when you start the virtual machine, allowing you to access the site at http://mastodon.dev (instead of http://localhost:3000):
The rails server, streaming server and webpack-dev-server will start up. You can then access your development site at http://mastodon.dev (or at http://localhost:3000 if you haven't installed vagrants-hostupdater). By default, your development environment will have an admin account created for you to use - the email address will be `admin@mastodon.dev` and the password will be `mastodonadmin`.
You should now have a working Mastodon instance, although it will not federate, as it is not publicly accessible. Should you need temporary federation for development and testing, see the Ngrok information in the [Development Guide](Development-guide.md).
By default, your instance's ActionMailer will use "Letter Opener Web" for email. This means that any email that would normally be sent, will instead be stored, and accessible at http://mastodon.dev/letter_opener - you can use this to verify a registered user account.
You are able to set environment variables, which are used for Mastodon configuration, by editing the `.env.vagrant` file. `.env.vagrant` is loaded when you run `vagrant ssh`.
Vagrant has mounted your mastodon folder inside the virtual machine. This means that any change to the files in the folder(e.g. the Rails controllers or the React components in /app) should immediately take effect on the live server. This allows you to make and test changes, and create new commits, without ever needing to access the virtual machine.
Should you need to access the virtual machine (for example, to manually restart the Rails process without restarting the box), run `vagrant ssh` from the mastodon folder. You will now be logged in as the `vagrant` user on the VirtualBox Ubuntu VM. You will want to `cd /vagrant` to see the app folder.
## Debugging
You can find the Rails server logs in in the `log` folder, which will often have the information you need.
If your Mastodon instance or Vagrant box are really not behaving, you can re-run the provisioning process. Stop the box with `vagrant halt`, and then run `vagrant destroy` - this will delete the virtual machine. You may then run `vagrant up` to create a new box, and re-run provisioning.
## Testing
To run the `rspec` tests and `rubocop` style checker, you may either:
* Install the relevant gems locally, or
* SSH into the virtual machine, `cd /vagrant`, and then run the commands
