You can set up one or moreFirebase Hosting sites in a single Firebaseproject. Since the sites are all in the same Firebase project, all the sites canaccess the other Firebase resources of the project.

• Each site has its ownhosting configuration.
• Each site hosts its own collection of content.
• Each site can have one or moreassociated domains.

By setting up multipleHosting sites within the same Firebase project, youcan more easily share Firebase resources between related sites and apps. Forexample, if you set up your blog, admin panel, and public app as individualsites in the same Firebase project, they can all share the sameFirebase Authentication user database, while also having their own unique domains orcontent.

Access the most currentFirebase Hosting features byupdating to the latest version of theFirebase CLI.

Step 2: Add additional sites

Add additional sites to a Firebase project using one of the following methods:

• Use the workflow in theHosting page of theFirebase console

• Use theFirebase CLI command:firebase hosting:sites:createSITE_ID

• Use theHosting REST API:projects.sites.create

For each of these methods, you'll specify aSITE_ID which is used to constructthe Firebase-provisioned default subdomains for the site:

• SITE_ID.web.app
• SITE_ID.firebaseapp.com

Because theSITE_ID is used for these URLs, the site ID has the followingrequirements:

• Must be a valid hostname label, meaning it cannot contain.,_, etc.
• Must be 30 characters or fewer
• Must be globally unique within Firebase

To each site, you can also optionallyadd custom domains to serve the same content andconfiguration to multiple URLs.

• Use the workflow in theHosting page of theFirebase console

• Use theFirebase CLI command:firebase hosting:sites:deleteSITE_ID

• Use theHosting REST API:projects.sites.delete

Note that you cannot delete the default site, which has the sameSITE_ID asyour Firebase project ID.

When you have multiple sites and you runFirebase CLI deploy commands, theCLI needs a way to communicate which settings should be deployed to eachsite. Withdeploy targets you can uniquely identifyaspecific site with aTARGET_NAME in yourfirebase.json configuration fileand in yourFirebase CLI commands fortesting or deploying to your sites.

To create a deploy target and apply aTARGET_NAME to aHosting site, runthe following CLI command from the root of your project directory:

firebase target:apply hostingTARGET_NAMERESOURCE_IDENTIFIER

Where the parameters are:

• TARGET_NAME — a unique name (that you've defined yourself) for theHosting site that you're deploying to

• RESOURCE_IDENTIFIER — theSITE_ID for theHosting siteaslisted in your Firebase project

For example, if you've created two sites (myapp-blog andmyapp-app) in yourFirebase project, you could apply a uniqueTARGET_NAME (blogandapp, respectively) to each site by running the following commands:

firebase target:apply hostingblog myapp-blog

firebase target:apply hostingapp myapp-app

The settings for deploy targets are stored in the.firebaserc file in yourproject directory, so you only need to set up deploy targets one time perproject.

Step 4: Define the hosting configuration for each site

Use a site's appliedTARGET_NAME when you're defining its hostingconfiguration in yourfirebase.json file.

• If yourfirebase.json file defines the configuration for multiple sites,use an array format:

  {  "hosting": [ {"target": "blog",  // "blog" is the applied TARGET_NAME for theHosting site "myapp-blog"      "public": "blog/dist",  // contents of this folder are deployed to the site "myapp-blog"      // ...    },    {"target": "app",  // "app" is the applied TARGET_NAME for theHosting site "myapp-app"      "public": "app/dist",  // contents of this folder are deployed to the site "myapp-app"      // ...      "rewrites": [...]  // You can define specificHosting configurations for each site    }  ]}

• If yourfirebase.json file defines the configuration for only one site,it's not necessary to use an array format:

  {  "hosting": {"target": "blog",      "public": "dist",      // ...      "rewrites": [...]  }}

Step 5: Test locally, preview changes, and deploy to your sites

Run any of the following commands from the root of your local project directory.

For deploys to preview channels, you don't specifyhosting in the--only flag because those commands canonly deploy yourHosting content and config.