diff --git a/projects/packages/publicize/.phan/baseline.php b/projects/packages/publicize/.phan/baseline.php
index 276871afd3219..e6d2be7e491bc 100644
--- a/projects/packages/publicize/.phan/baseline.php
+++ b/projects/packages/publicize/.phan/baseline.php
@@ -32,11 +32,13 @@
     'file_suppressions' => [
         'src/class-connections-post-field.php' => ['PhanPluginDuplicateConditionalNullCoalescing'],
         'src/class-keyring-helper.php' => ['PhanTypeMismatchArgumentProbablyReal', 'PhanTypeMismatchDefault'],
+        'src/class-publicize-assets.php' => ['PhanNoopNew'],
         'src/class-publicize-base.php' => ['PhanImpossibleCondition', 'PhanPluginDuplicateConditionalNullCoalescing', 'PhanPluginSimplifyExpressionBool', 'PhanSuspiciousMagicConstant', 'PhanTypeMismatchArgument', 'PhanTypeMismatchArgumentNullable', 'PhanTypeMismatchArgumentNullableInternal', 'PhanTypeMismatchDimFetch', 'PhanTypeMismatchReturn'],
         'src/class-publicize-setup.php' => ['PhanTypeMismatchArgument'],
         'src/class-publicize-ui.php' => ['PhanPluginDuplicateExpressionAssignmentOperation', 'PhanTypeMismatchReturnProbablyReal'],
         'src/class-publicize.php' => ['PhanParamSignatureMismatch', 'PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchArgument', 'PhanTypeMissingReturn'],
         'src/class-rest-controller.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanTypeMismatchReturnProbablyReal'],
+        'src/rest-endpoints/class-connections-controller.php' => ['PhanPluginMixedKeyNoKey'],
         'src/social-image-generator/class-post-settings.php' => ['PhanPluginDuplicateConditionalNullCoalescing'],
         'src/social-image-generator/class-rest-settings-controller.php' => ['PhanPluginMixedKeyNoKey'],
         'src/social-image-generator/class-settings.php' => ['PhanPluginDuplicateConditionalNullCoalescing'],
diff --git a/projects/packages/publicize/.phan/config.php b/projects/packages/publicize/.phan/config.php
index 7030e2aa8176c..075dd16643b9e 100644
--- a/projects/packages/publicize/.phan/config.php
+++ b/projects/packages/publicize/.phan/config.php
@@ -24,6 +24,7 @@
 			__DIR__ . '/../../../plugins/jetpack/_inc/lib/admin-pages/class.jetpack-admin-page.php', // class Jetpack_Admin_Page
 			__DIR__ . '/../../../plugins/jetpack/modules/subscriptions.php',                         // class Jetpack_Subscriptions
 			__DIR__ . '/../../../plugins/jetpack/functions.global.php',                              // function jetpack_render_tos_blurb
+			__DIR__ . '/../../../plugins/jetpack/_inc/lib/core-api/load-wpcom-endpoints.php', // function wpcom_rest_api_v2_load_plugin
 		),
 	)
 );
diff --git a/projects/packages/publicize/changelog/add-social-unitied-connections-endpoint b/projects/packages/publicize/changelog/add-social-unitied-connections-endpoint
new file mode 100644
index 0000000000000..5f31aa8db8050
--- /dev/null
+++ b/projects/packages/publicize/changelog/add-social-unitied-connections-endpoint
@@ -0,0 +1,4 @@
+Significance: minor
+Type: added
+
+Added wpcom/v3/publicize/connections endpoint
diff --git a/projects/packages/publicize/src/class-connection-fields.php b/projects/packages/publicize/src/class-connection-fields.php
new file mode 100644
index 0000000000000..a9de08bc176a3
--- /dev/null
+++ b/projects/packages/publicize/src/class-connection-fields.php
@@ -0,0 +1,170 @@
+<?php
+/**
+ * Publicize Connection Fields class.
+ *
+ * @package automattic/jetpack-publicize
+ */
+
+namespace Automattic\Jetpack\Publicize;
+
+/**
+ * Publicize Connection Fields class.
+ */
+class Connection_Fields {
+
+	/**
+	 * Get the publicize instance - properly typed
+	 *
+	 * @return Publicize
+	 */
+	protected static function publicize() {
+		/**
+		 * Publicize instance.
+		 *
+		 * @var Publicize $publicize
+		 */
+		global $publicize;
+
+		if ( ! $publicize && function_exists( 'publicize_init' ) ) {
+			// @phan-suppress-next-line PhanUndeclaredFunction - phan is dumb not to see the function_exists check
+			publicize_init();
+		}
+
+		return $publicize;
+	}
+
+	/**
+	 * Get the meta of a connection.
+	 *
+	 * @param array|object $connection The connection.
+	 * @return array
+	 */
+	protected static function get_connection_meta( $connection ) {
+
+		return self::publicize()->get_connection_meta( $connection );
+	}
+
+	/**
+	 * Get the ID of a connection.
+	 *
+	 * @param array $connection The connection.
+	 * @return string
+	 */
+	public static function get_connection_id( $connection ) {
+		return (string) self::publicize()->get_connection_id( $connection );
+	}
+
+	/**
+	 * Returns a display name for the Connection
+	 *
+	 * @param string       $service_name 'facebook', 'twitter', etc.
+	 * @param object|array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return string
+	 */
+	public static function get_display_name( $service_name, $connection ) {
+		return self::publicize()->get_display_name( $service_name, $connection );
+	}
+
+	/**
+	 * Returns the external handle for the Connection.
+	 *
+	 * @param string       $service_name 'facebook', 'linkedin', etc.
+	 * @param object|array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return string
+	 */
+	public static function get_external_handle( $service_name, $connection ) {
+		$cmeta = self::get_connection_meta( $connection );
+
+		switch ( $service_name ) {
+			case 'mastodon':
+				return $cmeta['external_display'] ?? '';
+
+			case 'bluesky':
+			case 'threads':
+				return $cmeta['external_name'] ?? '';
+
+			case 'instagram-business':
+				return $cmeta['connection_data']['meta']['username'] ?? '';
+
+			default:
+				return '';
+		}
+	}
+
+	/**
+	 * Returns the external ID for the Connection.
+	 *
+	 * @param object|array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return string
+	 */
+	public static function get_external_id( $connection ) {
+		$connection_meta = self::get_connection_meta( $connection );
+
+		return $connection_meta['external_id'] ?? '';
+	}
+
+	/**
+	 * Returns an external URL to the Connection's profile
+	 *
+	 * @param string       $service_name 'facebook', 'twitter', etc.
+	 * @param object|array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return false|string False on failure. URL on success.
+	 */
+	public static function get_profile_link( $service_name, $connection ) {
+		return self::publicize()->get_profile_link( $service_name, $connection );
+	}
+
+	/**
+	 * Returns a profile picture for the Connection
+	 *
+	 * @param object|array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return string
+	 */
+	public static function get_profile_picture( $connection ) {
+		return self::publicize()->get_profile_picture( $connection );
+	}
+
+	/**
+	 * Returns a display name for the Service
+	 *
+	 * @param string $service_name 'facebook', 'twitter', etc.
+	 * @return string
+	 */
+	public static function get_service_label( $service_name ) {
+		return self::publicize()->get_service_label( $service_name );
+	}
+
+	/**
+	 * Returns whether the Connection is shared
+	 *
+	 * @param array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return bool
+	 */
+	public static function is_shared( $connection ) {
+		return empty( self::get_user_id( $connection ) );
+	}
+
+	/**
+	 * Returns the status for the Connection
+	 *
+	 * @param array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return string
+	 */
+	public static function get_status( $connection ) {
+		return $connection['status'] ?? 'ok';
+	}
+
+	/**
+	 * Returns the user ID for the Connection
+	 *
+	 * @param array $connection The Connection object (WordPress.com) or array (Jetpack).
+	 * @return int
+	 */
+	public static function get_user_id( $connection ) {
+		$connection_meta = self::get_connection_meta( $connection );
+
+		$connection_data = $connection_meta['connection_data'];
+
+		return (int) $connection_data['user_id'];
+	}
+}
diff --git a/projects/packages/publicize/src/class-publicize-assets.php b/projects/packages/publicize/src/class-publicize-assets.php
index e74fe44dcf5bc..f3e718ae6b9f3 100644
--- a/projects/packages/publicize/src/class-publicize-assets.php
+++ b/projects/packages/publicize/src/class-publicize-assets.php
@@ -7,6 +7,8 @@
 
 namespace Automattic\Jetpack\Publicize;
 
+use Automattic\Jetpack\Publicize\Rest_Endpoints\Connections_Controller;
+
 /**
  * Publicize_Assets class.
  */
@@ -17,5 +19,6 @@ class Publicize_Assets {
 	 */
 	public static function configure() {
 		Publicize_Script_Data::configure();
+		new Connections_Controller();
 	}
 }
diff --git a/projects/packages/publicize/src/class-publicize-base.php b/projects/packages/publicize/src/class-publicize-base.php
index b88bd1a6b12ca..8494b8e1e9280 100644
--- a/projects/packages/publicize/src/class-publicize-base.php
+++ b/projects/packages/publicize/src/class-publicize-base.php
@@ -497,8 +497,8 @@ public function get_profile_link( $service_name, $connection ) {
 			return 'https://instagram.com/' . $cmeta['connection_data']['meta']['username'];
 		}
 
-		if ( 'threads' === $service_name && isset( $connection['external_name'] ) ) {
-			return 'https://www.threads.net/@' . $connection['external_name'];
+		if ( 'threads' === $service_name && isset( $cmeta['external_name'] ) ) {
+			return 'https://www.threads.net/@' . $cmeta['external_name'];
 		}
 
 		if ( 'mastodon' === $service_name && isset( $cmeta['external_name'] ) ) {
@@ -527,7 +527,7 @@ public function get_profile_link( $service_name, $connection ) {
 			}
 
 			$profile_url_query      = wp_parse_url( $cmeta['connection_data']['meta']['profile_url'], PHP_URL_QUERY );
-			$profile_url_query_args = null;
+			$profile_url_query_args = array();
 			wp_parse_str( $profile_url_query, $profile_url_query_args );
 
 			$id = null;
@@ -608,7 +608,7 @@ public function get_username( $service_name, $connection ) {
 	 * @param object|array $connection The Connection object (WordPress.com) or array (Jetpack).
 	 * @return string
 	 */
-	private function get_profile_picture( $connection ) {
+	public function get_profile_picture( $connection ) {
 		$cmeta = $this->get_connection_meta( $connection );
 
 		if ( isset( $cmeta['profile_picture'] ) ) {
diff --git a/projects/packages/publicize/src/rest-endpoints/class-base-controller.php b/projects/packages/publicize/src/rest-endpoints/class-base-controller.php
new file mode 100644
index 0000000000000..5dd19761093de
--- /dev/null
+++ b/projects/packages/publicize/src/rest-endpoints/class-base-controller.php
@@ -0,0 +1,90 @@
+<?php
+/**
+ * Base Controller class.
+ *
+ * @package automattic/jetpack-publicize
+ */
+
+namespace Automattic\Jetpack\Publicize\Rest_Endpoints;
+
+use Automattic\Jetpack\Status\Host;
+use WP_Error;
+use WP_REST_Controller;
+use WP_REST_Request;
+use WP_REST_Response;
+
+/**
+ * Base controller for Publicize endpoints.
+ */
+abstract class Base_Controller extends WP_REST_Controller {
+
+	/**
+	 * Constructor.
+	 */
+	public function __construct() {
+		$this->namespace = 'wpcom/v3';
+
+		$this->wpcom_is_wpcom_only_endpoint = true;
+	}
+
+	/**
+	 * Check if we are on WPCOM.
+	 *
+	 * @return bool
+	 */
+	public static function is_wpcom() {
+		return ( new Host() )->is_wpcom_simple();
+	}
+
+	/**
+	 * Filters out data based on ?_fields= request parameter
+	 *
+	 * @param array           $item    Item to prepare.
+	 * @param WP_REST_Request $request Full details about the request.
+	 *
+	 * @return WP_REST_Response filtered item
+	 */
+	public function prepare_item_for_response( $item, $request ) {
+		if ( ! is_callable( array( $this, 'get_fields_for_response' ) ) ) {
+			return rest_ensure_response( $item );
+		}
+
+		$fields = $this->get_fields_for_response( $request );
+
+		$response_data = array();
+		foreach ( $item as $field => $value ) {
+			if ( in_array( $field, $fields, true ) ) {
+				$response_data[ $field ] = $value;
+			}
+		}
+
+		return rest_ensure_response( $response_data );
+	}
+
+	/**
+	 * Verify that user can access Publicize data
+	 *
+	 * @return true|WP_Error
+	 */
+	public function get_items_permission_check() {
+		global $publicize;
+
+		if ( ! $publicize ) {
+			return new WP_Error(
+				'publicize_not_available',
+				__( 'Sorry, Jetpack Social is not available on your site right now.', 'jetpack-publicize-pkg' ),
+				array( 'status' => rest_authorization_required_code() )
+			);
+		}
+
+		if ( $publicize->current_user_can_access_publicize_data() ) {
+			return true;
+		}
+
+		return new WP_Error(
+			'invalid_user_permission_publicize',
+			__( 'Sorry, you are not allowed to access Jetpack Social data on this site.', 'jetpack-publicize-pkg' ),
+			array( 'status' => rest_authorization_required_code() )
+		);
+	}
+}
diff --git a/projects/packages/publicize/src/rest-endpoints/class-connections-controller.php b/projects/packages/publicize/src/rest-endpoints/class-connections-controller.php
new file mode 100644
index 0000000000000..2c5e4973ca6f7
--- /dev/null
+++ b/projects/packages/publicize/src/rest-endpoints/class-connections-controller.php
@@ -0,0 +1,254 @@
+<?php
+/**
+ * The Publicize Connections Controller class.
+ *
+ * @package automattic/jetpack-publicize
+ */
+
+namespace Automattic\Jetpack\Publicize\Rest_Endpoints;
+
+use Automattic\Jetpack\Connection\Client;
+use Automattic\Jetpack\Connection\Manager;
+use Automattic\Jetpack\Publicize\Connection_Fields;
+use WP_REST_Request;
+use WP_REST_Response;
+use WP_REST_Server;
+
+/**
+ * Connections Controller class.
+ */
+class Connections_Controller extends Base_Controller {
+
+	/**
+	 * Constructor.
+	 */
+	public function __construct() {
+		parent::__construct();
+
+		$this->rest_base = 'publicize/connections';
+
+		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
+	}
+
+	/**
+	 * Register the routes.
+	 */
+	public function register_routes() {
+		register_rest_route(
+			$this->namespace,
+			'/' . $this->rest_base,
+			array(
+				array(
+					'methods'             => WP_REST_Server::READABLE,
+					'callback'            => array( $this, 'get_items' ),
+					'permission_callback' => array( $this, 'get_items_permission_check' ),
+					'args'                => array(
+						'test_connections' => array(
+							'type'        => 'boolean',
+							'description' => __( 'Whether to test connections.', 'jetpack-publicize-pkg' ),
+						),
+					),
+				),
+				'schema' => array( $this, 'get_public_item_schema' ),
+			)
+		);
+	}
+
+	/**
+	 * Schema for the endpoint.
+	 *
+	 * @return array
+	 */
+	public function get_item_schema() {
+		$schema = array(
+			'$schema'    => 'http://json-schema.org/draft-04/schema#',
+			'title'      => 'jetpack-publicize-connection',
+			'type'       => 'object',
+			'properties' => array(
+				'connection_id'   => array(
+					'type'        => 'string',
+					'description' => __( 'Connection ID of the connected account.', 'jetpack-publicize-pkg' ),
+				),
+				'display_name'    => array(
+					'type'        => 'string',
+					'description' => __( 'Display name of the connected account.', 'jetpack-publicize-pkg' ),
+				),
+				'external_handle' => array(
+					'type'        => 'string',
+					'description' => __( 'The external handle or username of the connected account.', 'jetpack-publicize-pkg' ),
+				),
+				'external_id'     => array(
+					'type'        => 'string',
+					'description' => __( 'The external ID of the connected account.', 'jetpack-publicize-pkg' ),
+				),
+				'profile_link'    => array(
+					'type'        => 'string',
+					'description' => __( 'Profile link of the connected account.', 'jetpack-publicize-pkg' ),
+				),
+				'profile_picture' => array(
+					'type'        => 'string',
+					'description' => __( 'URL of the profile picture of the connected account.', 'jetpack-publicize-pkg' ),
+				),
+				'service_label'   => array(
+					'type'        => 'string',
+					'description' => __( 'Human-readable label for the Jetpack Social service.', 'jetpack-publicize-pkg' ),
+				),
+				'service_name'    => array(
+					'type'        => 'string',
+					'description' => __( 'Alphanumeric identifier for the Jetpack Social service.', 'jetpack-publicize-pkg' ),
+				),
+				'shared'          => array(
+					'type'        => 'boolean',
+					'description' => __( 'Whether the connection is shared with other users.', 'jetpack-publicize-pkg' ),
+				),
+				'status'          => array(
+					'type'        => 'string',
+					'description' => __( 'The connection status.', 'jetpack-publicize-pkg' ),
+					'enum'        => array(
+						'ok',
+						'broken',
+					),
+				),
+				'user_id'         => array(
+					'type'        => 'integer',
+					'description' => __( 'ID of the user the connection belongs to.', 'jetpack-publicize-pkg' ),
+				),
+			),
+		);
+
+		return $this->add_additional_fields_schema( $schema );
+	}
+
+	/**
+	 * Get all connections. Meant to be called directly only on WPCOM.
+	 *
+	 * @param bool $run_tests Whether to run tests on the connections.
+	 *
+	 * @return array
+	 */
+	protected static function get_all_connections( $run_tests = false ) {
+		/**
+		 * Publicize instance.
+		 *
+		 * @var \Automattic\Jetpack\Publicize\Publicize $publicize
+		 */
+		global $publicize;
+
+		$items = array();
+
+		$test_results = $run_tests ? self::get_connections_test_status() : array();
+
+		foreach ( (array) $publicize->get_services( 'connected' ) as $service_name => $connections ) {
+			foreach ( $connections as $connection ) {
+
+				$connection_id = Connection_Fields::get_connection_id( $connection );
+
+				$items[] = array(
+					'connection_id'   => $connection_id,
+					'display_name'    => Connection_Fields::get_display_name( $service_name, $connection ),
+					'external_handle' => Connection_Fields::get_external_handle( $service_name, $connection ),
+					'external_id'     => Connection_Fields::get_external_id( $connection ),
+					'profile_link'    => Connection_Fields::get_profile_link( $service_name, $connection ),
+					'profile_picture' => Connection_Fields::get_profile_picture( $connection ),
+					'service_label'   => Connection_Fields::get_service_label( $service_name ),
+					'service_name'    => $service_name,
+					'shared'          => Connection_Fields::is_shared( $connection ),
+					'status'          => $test_results[ $connection_id ] ?? 'ok',
+					'user_id'         => Connection_Fields::get_user_id( $connection ),
+				);
+			}
+		}
+
+		return $items;
+	}
+
+	/**
+	 * Get a list of publicize connections.
+	 *
+	 * @param bool $run_tests Whether to run tests on the connections.
+	 *
+	 * @return array
+	 */
+	public static function get_connections( $run_tests = false ) {
+		if ( self::is_wpcom() ) {
+			return self::get_all_connections( $run_tests );
+		}
+
+		$site_id = Manager::get_site_id( true );
+		if ( ! $site_id ) {
+			return array();
+		}
+
+		$path = add_query_arg(
+			array( 'test_connections' => $run_tests ),
+			sprintf( '/sites/%d/publicize/connections', $site_id )
+		);
+
+		$response = Client::wpcom_json_api_request_as_user( $path, 'v3', array( 'method' => 'GET' ) );
+
+		if ( is_wp_error( $response ) || 200 !== wp_remote_retrieve_response_code( $response ) ) {
+			// TODO log error.
+			return array();
+		}
+
+		$body = wp_remote_retrieve_body( $response );
+
+		$items = json_decode( $body, true );
+
+		return $items ? $items : array();
+	}
+
+	/**
+	 * Get list of connected Publicize connections.
+	 *
+	 * @param WP_REST_Request $request Full details about the request.
+	 *
+	 * @return WP_REST_Response suitable for 1-page collection
+	 */
+	public function get_items( $request ) {
+		$items = array();
+
+		$run_tests = $request->get_param( 'test_connections' );
+
+		foreach ( self::get_connections( $run_tests ) as $item ) {
+			$data = $this->prepare_item_for_response( $item, $request );
+
+			$items[] = $this->prepare_response_for_collection( $data );
+		}
+
+		$response = rest_ensure_response( $items );
+		$response->header( 'X-WP-Total', (string) count( $items ) );
+		$response->header( 'X-WP-TotalPages', '1' );
+
+		return $response;
+	}
+
+	/**
+	 * Get the connections test status.
+	 *
+	 * @return array
+	 */
+	protected static function get_connections_test_status() {
+		/**
+		 * Publicize instance.
+		 *
+		 * @var \Automattic\Jetpack\Publicize\Publicize $publicize
+		 */
+		global $publicize;
+
+		$test_results = $publicize->get_publicize_conns_test_results();
+
+		$test_results_map = array();
+
+		foreach ( $test_results as $test_result ) {
+			// Compare to `true` because the API returns a 'must_reauth' for LinkedIn.
+			$test_results_map[ $test_result['connectionID'] ] = true === $test_result['connectionTestPassed'] ? 'ok' : 'broken';
+		}
+
+		return $test_results_map;
+	}
+}
+
+if ( Base_Controller::is_wpcom() ) {
+	wpcom_rest_api_v2_load_plugin( Connections_Controller::class );
+}