Deploying to production is always a little nerve-wracking. What happens if the new version of the site has bugs you didn’t catch? One-click rollbacks in Firebase Hosting allow you to safely go back the last working version, but how can we ensure that the problem doesn’t happen in the first place?

The answer is simple. Test your site in a mirrored production environment. Fortunately for us, the Firebase CLI makes it simple to setup and deploy to multiple environments.

Adding a new environment

Adding and switching between environments with the Firebase CLI is as simple as one command: firebase use.

When you first initialize your Firebase Hosting project with firebase init you specify what project you want to deploy your app to. This is your default project. The use command allows you to add another project.

$ firebase use --add

This command prompts you to choose from one of your existing projects:

$ firebase use --add
$ ? Which project do you want to add? (Use arrow keys)
  my-production-project
> my-staging-project
  my-dev-project

Select the project you want to use for a different environment, and then give it an alias. The alias can really be whatever you want, but it’s common to use aliases like “development”, “staging”, or “production”.

$ firebase use --add
$ ? Which project do you want to add? (Use arrow keys)
  my-production-project
> my-staging-project
  my-dev-project
? What alias do you want to use for this project? (e.g. staging) staging
Created alias staging my-staging-project.
Now using alias staging (my-staging-project)

Once you’ve created a new alias, it will be set as the current environment for deployment. Running firebase deploy will deploy your app to that environment.

Switching environments

If you want to switch to another environment, just provide the alias in the use command.

$ firebase use default # sets environment to the default alias
$ firebase use staging # sets environment to the staging alias

For a single command, you can also specify the environment using the -P flag:

$ firebase deploy -P staging # deploy to staging alias

That’s it!

That’s all there is to switching environments with Firebase Hosting. If you want a guided tour on getting setup, then check out our screencast. Let us know what you think in the comments!