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In this step, you'll deploy your application to the web.

Type polymer build to build your Polymer application for production.

You can serve different builds of your app to browsers with different capabilities. The Polymer Starter Kit is configured to create three builds:

  • A bundled, minified build with a service worker, compiled to ES5 for compatibility with older browsers.
  • A bundled, minified build with a service worker. ES6 code is served as-is. This build is for browsers that can handle ES6 code.
  • An unbundled, minified build with a service worker. ES6 code is served as-is. This build is for browsers that support HTTP/2 push.

In this step, you'll deploy the bundled, compiled build (es5-bundled) for maximum compatibility. Serving the other builds requires a more complex serving setup.

Builds are configured in the builds object in polymer.json, a configuration file in the root project folder:


"builds": [
    "preset": "es5-bundled"
    "preset": "es6-bundled"
    "preset": "es6-unbundled"

The builds will be output to subfolders under the build/ folder as follows:


To configure a custom build, you can use command line options, or edit polymer.json. Run polymer help build for the full list of available options and optimizations. Also, see the documentation on the polymer.json specification and building your Polymer application for production.

Polymer applications can be deployed to any web server.

This template uses the <app-location> element to enable URL-based routing, which requires that the server serve the index.html entry point for all routes.

You can follow one of the sections below to deploy this app to either Google AppEngine or Firebase Static Hosting, which are both free and secure approaches for deploying a Polymer app. The approach is similar for other hosting providers.

  1. Download the Google App Engine SDK and follow the instructions for your platform to install it. This tutorial uses the Python SDK.

  2. Sign up for an AppEngine account.

  3. Open the project dashboard and create a new project.

    • Click the Create Project button.
    • Type a project name.
    • Click the Create button.

    The App Engine gives you a project ID based on the name of your project. Make note of this ID.

  4. cd into the main folder for your app (e.g. my-app/).

  5. Create an app.yaml file with the following contents:

    runtime: python27
    api_version: 1
    threadsafe: yes
    - url: /bower_components
      static_dir: build/es5-bundled/bower_components
      secure: always
    - url: /images
      static_dir: build/es5-bundled/images
      secure: always
    - url: /src
      static_dir: build/es5-bundled/src
      secure: always
    - url: /manifest.json
      static_files: build/es5-bundled/manifest.json
      upload: build/es5-bundled/manifest.json
      secure: always
    - url: /service-worker.js
      static_files: build/es5-bundled/service-worker.js
      upload: build/es5-bundled/service-worker.js
      secure: always
    - url: /.*
      static_files: build/es5-bundled/index.html
      upload: build/es5-bundled/index.html
      secure: always
  6. Set your project id to the ID given to your app by the App Engine. For example:

    gcloud config set project my-app-164409
  7. Create your app:

    gcloud app create

    You will need to select a region for your app to be deployed in. This can't be changed.

  8. Deploy your app:

    gcloud app deploy
  9. Your app will be available online at its designated URL. For example:

    Open your app URL in your browser by typing this command:

    gcloud app browse

The instructions below are based on the Firebase hosting quick start guide.

  1. Sign up for a Firebase account.

  2. Go to to create a new app. Make note of the project ID associated with your app.

    Welcome to Firebase showing Project ID

  3. Install the Firebase command line tools.

    npm install -g firebase-tools
  4. cd into your project folder.

  5. Inititalize the Firebase application.

    firebase login
    firebase init
  6. Firebase asks you for a project to associate with your app. Select the one you created earlier.

  7. Firebase asks you the name of your app's public folder. Enter build/es5-bundled/.

  8. Edit your firebase configuration to add support for URL routing. The final firebase.json file should look something like this:

      "hosting": {
        "public": "build/es5-bundled/",
        "rewrites": [
            "source": "**/!(*.*)",
            "destination": "/index.html"

    This instructs Firebase to serve up index.html for any URLs that don't otherwise end in a file extension.

  9. Deploy your project.

    firebase deploy

    The URL to your live site is listed in the output. You can also open the site in your default browser by running firebase open hosting:site.