# Get started with REST

To start using the Google Photos Library API, configure your project by enabling the API via
the Google API Console and setting up an OAuth 2.0 client ID.

Your application interacts with Google Photos on behalf of a
Google Photos user. For instance, when you create albums in a user's
Google Photos library or upload media items to a user's
Google Photos account, the user authorizes these API requests via the
[OAuth 2.0](https://developers.google.com/identity/protocols/OAuth2) protocol.

The OAuth 2.0 client ID allows your application users to sign in, authenticate,
and thereby use the Library API. The Library API does not support
service accounts; to use this API, users must be signed in to a valid Google
Account.

## Configure your app

### Enable the API

Before you can use the Library API, you must enable it for your project.

1. Go to the [Google API Console](https://console.developers.google.com/apis/library).
2. From the menu bar, select a project or create a new project.
3. To open the Google API Library, from the Navigation menu, select **APIs \& Services \> Library**.
4. Search for "Google Photos Library API". Select the correct result and click **Enable**.

### Request an OAuth 2.0 client ID

Follow the steps below to request an OAuth client ID and configure it for your
application. This example uses an application where the entire OAuth flow is
handled server-side, such as the one in our samples. The setup process may vary
for other [implementation scenarios](https://developers.google.com/identity/protocols/OAuth2).

1. Go to the [Google API Console](https://console.developers.google.com/apis/library) and select your project.
2. From the menu, select **APIs \& Services \> Credentials**.
3. On the **Credentials** page, click **Create Credentials \> OAuth client ID**.
4. Select your **Application type** . In this example, the application type is **Web application**.
5. Register the origins from which your app is allowed to access the Google APIs
   as follows:

   1. To identify the client ID, enter a name.
   2. In the **Authorized JavaScript origins** field, enter the origin for your
      app. This field doesn't allow wildcards.

      You can enter multiple origins to allow your app to run on different
      protocols, domains, or subdomains. The URLs you enter are allowed to
      start an OAuth request.

      The following example shows a local development URL (our samples use
      `localhost:8080`) and a production URL.

          http://localhost:8080
          https://myproductionurl.example.com

   3. The **Authorized redirect URI** field is the endpoint that receives
      responses from the OAuth 2.0 server. Typically, this includes your
      development environment and points to a path in your application.

          http://localhost:8080/auth/google/callback
          https://myproductionurl.example.com/auth/google/callback

   4. Click **Create**.

<!-- -->

6. From the resulting OAuth client dialog, copy the following:

   - Client ID
   - Client secret

   Your app can access the enabled Google APIs using these values.

Before you can launch a public application that accesses the Library API,
your app must be reviewed by Google. An "Unverified app" message appears on the
screen when you test your application, until it is
[verified](https://support.google.com/cloud/answer/7454865).

## Try out the sample

Now that you've configured your project for use with the Library API,
check out the [sample app](https://developers.google.com/photos/library/samples) on GitHub. The sample app
demonstrates how you can build a smart photo frame using the Library API.