diff --git a/modules/ppcp-onboarding/services.php b/modules/ppcp-onboarding/services.php
index ac87010b4c..3c95775101 100644
--- a/modules/ppcp-onboarding/services.php
+++ b/modules/ppcp-onboarding/services.php
@@ -18,6 +18,7 @@
 use WooCommerce\PayPalCommerce\Onboarding\Assets\OnboardingAssets;
 use WooCommerce\PayPalCommerce\Onboarding\Endpoint\LoginSellerEndpoint;
 use WooCommerce\PayPalCommerce\Onboarding\Render\OnboardingRenderer;
+use WooCommerce\PayPalCommerce\Onboarding\Onboarding_REST_Controller;
 
 return array(
 	'api.sandbox-host'                          => static function ( $container ): string {
@@ -207,4 +208,7 @@
 			$partner_referrals_sandbox
 		);
 	},
+	'onboarding.rest'                           => static function( $container ) : Onboarding_REST_Controller {
+		return new Onboarding_REST_Controller( $container );
+	},
 );
diff --git a/modules/ppcp-onboarding/src/Assets/class-onboardingassets.php b/modules/ppcp-onboarding/src/Assets/class-onboardingassets.php
index 8cc1d87b41..33ff787305 100644
--- a/modules/ppcp-onboarding/src/Assets/class-onboardingassets.php
+++ b/modules/ppcp-onboarding/src/Assets/class-onboardingassets.php
@@ -90,16 +90,25 @@ public function register(): bool {
 		wp_localize_script(
 			'ppcp-onboarding',
 			'PayPalCommerceGatewayOnboarding',
-			array(
-				'endpoint'      => home_url( \WC_AJAX::get_endpoint( LoginSellerEndpoint::ENDPOINT ) ),
-				'nonce'         => wp_create_nonce( $this->login_seller_endpoint::nonce() ),
-				'paypal_js_url' => 'https://www.paypal.com/webapps/merchantboarding/js/lib/lightbox/partner.js',
-			)
+			$this->get_script_data()
 		);
 
 		return true;
 	}
 
+	/**
+	 * Returns the data associated to the onboarding script.
+	 *
+	 * @return array
+	 */
+	public function get_script_data() {
+		return array(
+			'endpoint'      => home_url( \WC_AJAX::get_endpoint( LoginSellerEndpoint::ENDPOINT ) ),
+			'nonce'         => wp_create_nonce( $this->login_seller_endpoint::nonce() ),
+			'paypal_js_url' => 'https://www.paypal.com/webapps/merchantboarding/js/lib/lightbox/partner.js',
+		);
+	}
+
 	/**
 	 * Enqueues the necessary scripts.
 	 *
diff --git a/modules/ppcp-onboarding/src/class-onboarding-rest-controller.php b/modules/ppcp-onboarding/src/class-onboarding-rest-controller.php
new file mode 100644
index 0000000000..5bfa06eac4
--- /dev/null
+++ b/modules/ppcp-onboarding/src/class-onboarding-rest-controller.php
@@ -0,0 +1,311 @@
+<?php
+/**
+ * Onboarding REST controller.
+ *
+ * @package WooCommerce\PayPalCommerce\Onboarding
+ */
+
+declare(strict_types=1);
+
+namespace WooCommerce\PayPalCommerce\Onboarding;
+
+use Psr\Container\ContainerInterface;
+use WooCommerce\PayPalCommerce\Onboarding\State;
+use WooCommerce\PayPalCommerce\WcGateway\Gateway\PayPalGateway;
+
+/**
+ * Exposes and handles REST routes related to onboarding.
+ */
+class Onboarding_REST_Controller {
+
+	/**
+	 * REST namespace.
+	 *
+	 * @var string
+	 */
+	protected $rest_namespace = 'wc-paypal/v1';
+
+	/**
+	 * REST base.
+	 *
+	 * @var string
+	 */
+	protected $rest_base = 'onboarding';
+
+	/**
+	 * Module container with access to plugin services.
+	 *
+	 * @var ContainerInterface
+	 */
+	private $container = null;
+
+	/**
+	 * Used to temporarily store URL arguments to add to the return URL associated to a signup link.
+	 *
+	 * @var array
+	 */
+	private $return_url_args = array();
+
+
+	/**
+	 * OnboardingRESTController constructor.
+	 *
+	 * @param ContainerInterface $container Module container with access to plugin services.
+	 */
+	public function __construct( ContainerInterface $container ) {
+		$this->container = $container;
+	}
+
+	/**
+	 * Registers REST routes under 'wc-paypal/v1/onboarding'.
+	 * Specifically:
+	 * - `/onboarding/get-params`, which returns information useful to display an onboarding button.
+	 * - `/onboarding/get-status`, which returns information about the current environment and its onboarding state.
+	 * - `/onboarding/set-credentials`, which allows setting merchant/API credentials.
+	 */
+	public function register_routes() {
+		register_rest_route(
+			$this->rest_namespace,
+			'/' . $this->rest_base . '/get-params',
+			array(
+				'methods'             => 'POST',
+				'callback'            => array( $this, 'get_params' ),
+				'permission_callback' => array( $this, 'check_permission' ),
+			)
+		);
+
+		register_rest_route(
+			$this->rest_namespace,
+			'/' . $this->rest_base . '/get-status',
+			array(
+				'methods'             => 'GET',
+				'callback'            => array( $this, 'get_status' ),
+				'permission_callback' => array( $this, 'check_permission' ),
+			)
+		);
+
+		register_rest_route(
+			$this->rest_namespace,
+			'/' . $this->rest_base . '/set-credentials',
+			array(
+				'methods'             => 'POST',
+				'callback'            => array( $this, 'set_credentials' ),
+				'permission_callback' => array( $this, 'check_permission' ),
+			)
+		);
+	}
+
+	/**
+	 * Validate the requester's permissions.
+	 *
+	 * @param WP_REST_Request $request The request.
+	 * @return bool
+	 */
+	public function check_permission( $request ) {
+		return current_user_can( 'install_plugins' );
+	}
+
+	/**
+	 * Callback for the `/onboarding/get-params` endpoint.
+	 *
+	 * @param WP_REST_Request $request The request.
+	 * @return array
+	 */
+	public function get_params( $request ) {
+		$params = $request->get_json_params();
+
+		$environment = ( isset( $params['environment'] ) && in_array( $params['environment'], array( 'production', 'sandbox' ), true ) ) ? $params['environment'] : 'sandbox';
+
+		return array(
+			'scriptURL'               => trailingslashit( $this->container->get( 'onboarding.url' ) ) . 'assets/js/onboarding.js',
+			'scriptData'              => $this->container->get( 'onboarding.assets' )->get_script_data(),
+			'environment'             => $environment,
+			'onboardCompleteCallback' => 'ppcp_onboarding_' . $environment . 'Callback',
+			'signupLink'              => $this->generate_signup_link( $environment, ( ! empty( $params['returnUrlArgs'] ) ? $params['returnUrlArgs'] : array() ) ),
+		);
+	}
+
+	/**
+	 * Callback for the `/onboarding/get-status` endpoint.
+	 *
+	 * @param WP_REST_Request $request The request.
+	 * @return array
+	 */
+	public function get_status( $request ) {
+		$environment = $this->container->get( 'onboarding.environment' );
+		$state       = $this->container->get( 'onboarding.state' );
+
+		return array(
+			'environment' => $environment->current_environment(),
+			'onboarded'   => ( $state->current_state() >= State::STATE_ONBOARDED ),
+			'state'       => $this->get_onboarding_state_name( $state->current_state() ),
+			'sandbox'     => array(
+				'state'     => $this->get_onboarding_state_name( $state->sandbox_state() ),
+				'onboarded' => ( $state->sandbox_state() >= State::STATE_ONBOARDED ),
+			),
+			'production'  => array(
+				'state'     => $this->get_onboarding_state_name( $state->production_state() ),
+				'onboarded' => ( $state->production_state() >= State::STATE_ONBOARDED ),
+			),
+		);
+	}
+
+	/**
+	 * Callback for the `/onboarding/set-credentials` endpoint.
+	 *
+	 * @param WP_REST_Request $request The request.
+	 * @return WP_Error|array
+	 */
+	public function set_credentials( $request ) {
+		static $credential_keys = array(
+			'merchant_id',
+			'merchant_email',
+			'client_id',
+			'client_secret',
+		);
+
+		// Sanitize params.
+		$params = array_filter( array_map( 'trim', $request->get_json_params() ) );
+
+		// Validate 'environment'.
+		if ( empty( $params['environment'] ) || ! in_array( $params['environment'], array( 'sandbox', 'production' ), true ) ) {
+			return new \WP_Error(
+				'woocommerce_paypal_payments_invalid_environment',
+				sprintf(
+					/* translators: placeholder is an arbitrary string. */
+					__( 'Environment "%s" is invalid. Use "sandbox" or "production".', 'woocommerce-paypal-payments' ),
+					isset( $params['environment'] ) ? $params['environment'] : ''
+				),
+				array( 'status' => 400 )
+			);
+		}
+
+		// Validate the other fields.
+		$missing_keys = array_values( array_diff( $credential_keys, array_keys( $params ) ) );
+		if ( $missing_keys ) {
+			return new \WP_Error(
+				'woocommerce_paypal_payments_credentials_incomplete',
+				sprintf(
+					/* translators: placeholder is a comma-separated list of fields. */
+					__( 'Credentials are incomplete. Missing fields: %s.', 'woocommerce-paypal-payments' ),
+					implode( ', ', $missing_keys )
+				),
+				array(
+					'missing_fields' => $missing_keys,
+					'status'         => 400,
+				)
+			);
+		}
+
+		$settings     = $this->container->get( 'wcgateway.settings' );
+		$skip_persist = true;
+
+		$sandbox_on = ( 'sandbox' === $params['environment'] );
+		if ( ! $settings->has( 'sandbox_on' ) || ( (bool) $settings->get( 'sandbox_on' ) !== $sandbox_on ) ) {
+			$settings->set( 'sandbox_on', $sandbox_on );
+			$skip_persist = false;
+		}
+
+		// Enable gateway.
+		if ( ! $settings->has( 'enabled' ) || ! $settings->get( 'enabled' ) ) {
+			$settings->set( 'enabled', true );
+			$skip_persist = false;
+		}
+
+		foreach ( WC()->payment_gateways->payment_gateways() as $gateway ) {
+			if ( PayPalGateway::ID === $gateway->id ) {
+				$gateway->update_option( 'enabled', 'yes' );
+				break;
+			}
+		}
+
+		// Update settings.
+		foreach ( $credential_keys as $key ) {
+			$value   = $params[ $key ];
+			$env_key = $key . '_' . $params['environment'];
+
+			if ( ! $settings->has( $key ) || ! $settings->has( $env_key ) || $settings->get( $key ) !== $value || $settings->get( $env_key ) !== $value ) {
+				$settings->set( $key, $value );
+				$settings->set( $env_key, $value );
+				$skip_persist = false;
+			}
+		}
+
+		if ( ! $skip_persist && ! $settings->persist() ) {
+			return new \WP_Error(
+				'woocommerce_paypal_payments_credentials_not_saved',
+				__( 'An error occurred while saving the credentials.', 'woocommerce-paypal-payments' ),
+				array(
+					'status' => 500,
+				)
+			);
+		}
+
+		return array();
+	}
+
+	/**
+	 * Appends URL parameters stored in this class to a given URL.
+	 *
+	 * @hooked woocommerce_paypal_payments_partner_config_override_return_url - 10
+	 * @param string $url URL.
+	 * @return string The URL with the stored URL parameters added to it.
+	 */
+	public function add_args_to_return_url( $url ) {
+		return add_query_arg( $this->return_url_args, $url );
+	}
+
+	/**
+	 * Translates an onboarding state to a string.
+	 *
+	 * @param int $state An onboarding state to translate as returned by {@link State} methods.
+	 * @return string A string representing the state: "start", "progressive" or "onboarded".
+	 * @see State::current_state(), State::sandbox_state(), State::production_state().
+	 */
+	public function get_onboarding_state_name( $state ) {
+		$name = 'unknown';
+
+		switch ( absint( $state ) ) {
+			case State::STATE_START:
+				$name = 'start';
+				break;
+			case State::STATE_PROGRESSIVE:
+				$name = 'progressive';
+				break;
+			case State::STATE_ONBOARDED:
+				$name = 'onboarded';
+				break;
+			default:
+				break;
+
+		}
+
+		return $name;
+	}
+
+	/**
+	 * Generates a signup link for onboarding for a given environment and optionally adding certain URL arguments
+	 * to the URL users are redirected after completing the onboarding flow.
+	 *
+	 * @param string $environment The environment to use. Either 'sandbox' or 'production'. Defaults to 'sandbox'.
+	 * @param array  $url_args An array of URL arguments to add to the return URL via {@link add_query_arg()}.
+	 * @return string
+	 */
+	private function generate_signup_link( $environment = 'sandbox', $url_args = array() ) {
+		$this->return_url_args = ( ! empty( $url_args ) && is_array( $url_args ) ) ? $url_args : array();
+
+		if ( $this->return_url_args ) {
+			add_filter( 'woocommerce_paypal_payments_partner_config_override_return_url', array( $this, 'add_args_to_return_url' ) );
+		}
+
+		$link = $this->container->get( 'onboarding.render' )->get_signup_link( 'production' === $environment );
+
+		if ( $this->return_url_args ) {
+			remove_filter( 'woocommerce_paypal_payments_partner_config_override_return_url', array( $this, 'add_args_to_return_url' ) );
+			$this->return_url_args = array();
+		}
+
+		return $link;
+	}
+
+}
diff --git a/modules/ppcp-onboarding/src/class-onboardingmodule.php b/modules/ppcp-onboarding/src/class-onboardingmodule.php
index f5dbf0ec51..3526f7c330 100644
--- a/modules/ppcp-onboarding/src/class-onboardingmodule.php
+++ b/modules/ppcp-onboarding/src/class-onboardingmodule.php
@@ -41,7 +41,6 @@ public function setup(): ServiceProviderInterface {
 	 * @param ContainerInterface|null $container The container.
 	 */
 	public function run( ContainerInterface $container = null ) {
-
 		$asset_loader = $container->get( 'onboarding.assets' );
 		/**
 		 * The OnboardingAssets.
@@ -100,6 +99,10 @@ static function () use ( $container ) {
 				$endpoint->handle_request();
 			}
 		);
+
+		// Initialize REST routes at the appropriate time.
+		$rest_controller = $container->get( 'onboarding.rest' );
+		add_action( 'rest_api_init', array( $rest_controller, 'register_routes' ) );
 	}
 
 	/**