Building a Custom Registrar Integration

The Domain Seller addon uses an Integration Registry pattern. Each registrar is a PHP class that implements Domain_Selling_Capability and registers itself via the wu_domain_seller_register_capabilities action hook.

This guide shows how to wire in a custom registrar.

The interface

Your class must implement WP_Ultimo\Integrations\Capabilities\Domain_Selling_Capability and extend WP_Ultimo\Integrations\Base_Capability_Module.

Required methods:

namespace My\Plugin\Capabilities;

use WP_Ultimo\Integrations\Base_Capability_Module;
use WP_Ultimo\Integrations\Capabilities\Domain_Selling_Capability;

class My_Registrar_Selling extends Base_Capability_Module implements Domain_Selling_Capability {

    // --- Required identity methods (from Base_Capability_Module) ---

    public function get_capability_id(): string {
        return 'domain-selling';  // always 'domain-selling'
    }

    public function get_title(): string {
        return __('Domain Selling', 'my-plugin');
    }

    public function get_explainer_lines(): array {
        return [
            'will'     => [__('Enable domain registration via My Registrar.', 'my-plugin')],
            'will_not' => [],
        ];
    }

    // --- Core required methods (from Domain_Selling_Capability) ---

    /** Pull all available TLDs and wholesale pricing. */
    public function sync_tlds(): array { ... }

    /** Check availability of $domain_name across $tlds. */
    public function search_domains(string $domain_name, array $tlds = []): array { ... }

    /** Get wholesale price for a TLD for N years. */
    public function get_domain_pricing(string $tld, int $years = 1): array { ... }

    /** Register a domain. Returns ['success' => true, 'expiry_date' => '...'] on success. */
    public function register_domain(string $domain_name, array $registrant_info, int $years = 1): array { ... }

    /** Renew a domain for N years. */
    public function renew_domain(string $domain_name, int $years = 1): array { ... }

    /** Get registration status, expiry date, nameservers. */
    public function get_domain_info(string $domain_name): array { ... }

    /** Test API credentials and connectivity. */
    public function test_connection(): array { ... }
}

Optional methods

Implement these to unlock additional features. The addon detects support via method_exists():

Method	Unlocks
`supports_whois_privacy(): bool`	WHOIS privacy option in product settings
`enable_whois_privacy(string $domain_name): array`	Auto-enables privacy at registration
`get_dns_records(string $domain_name): array`	Customer DNS view tab
`add_dns_record(string $domain_name, array $record_data): array`	Customer can add DNS records
`update_dns_record(string $domain, string $record_id, array $record_data): array`	Customer can edit DNS records
`delete_dns_record(string $domain, string $record_id, array $data): array`	Customer can delete DNS records
`update_nameservers(string $domain_name, array $nameservers): array`	Nameserver management
`get_epp_code(string $domain_name): array`	Domain transfer (outgoing)
`transfer_domain(string $domain, string $auth_code, array $registrant_info, array $options): array`	Domain transfer (incoming)

Return value convention

All methods return an array with at minimum a success key:

// Success
return ['success' => true, 'data' => [...]];

// Failure
return ['success' => false, 'message' => 'Human-readable error'];

Registering your capability

add_action('wu_domain_seller_register_capabilities', function(\WP_Ultimo\Integrations\Integration_Registry $registry) {
    $registry->add_capability('my-registrar', new \My\Plugin\Capabilities\My_Registrar_Selling());
});

The first argument to add_capability() is the provider ID — a lowercase slug used to identify your registrar in settings, product configuration, and log channels. Use something unique (e.g., your company slug).

Adding credential fields to the wizard

To let admins enter credentials through the setup wizard, register your integration:

add_action('wu_domain_seller_register_integrations', function(\WP_Ultimo\Integrations\Integration_Registry $registry) {
    $registry->add_integration('my-registrar', [
        'name'   => __('My Registrar', 'my-plugin'),
        'fields' => [
            [
                'id'    => 'my_registrar_api_key',
                'label' => __('API Key', 'my-plugin'),
                'type'  => 'text',
            ],
            [
                'id'    => 'my_registrar_api_secret',
                'label' => __('API Secret', 'my-plugin'),
                'type'  => 'password',
            ],
        ],
    ]);
});

Credentials are stored as network options using the field IDs as keys. Retrieve them in your capability class with wu_get_setting('my_registrar_api_key').

Hooks for post-registration actions

Use these actions to trigger webhooks, provisioning, notifications, or CRM updates:

// After successful domain registration
add_action('wu_domain_registration_completed', function($payment, $registration_data, $result) {
    // $registration_data: domain_name, provider_id, years, expiry_date, customer_id
    // $result: raw registrar response
    my_crm_update_domain($registration_data['domain_name'], $registration_data['customer_id']);
}, 10, 3);

// After registration failure
add_action('wu_domain_registration_failed', function($payment, $registration_data, $error_message) {
    my_alert_team("Domain registration failed: {$registration_data['domain_name']} — {$error_message}");
}, 10, 3);

// After successful renewal
add_action('wu_domain_renewal_completed', function($payment, $renewal_data, $result) {
    // Update your billing system, send a receipt, etc.
}, 10, 3);

// After renewal failure
add_action('wu_domain_renewal_failed', function($payment, $renewal_data, $error_message) {
    // Alert, retry logic, etc.
}, 10, 3);

// After domain transfer completes
add_action('wu_domain_transfer_completed', function($domain, $transfer_data) {
    // $domain is a WP_Ultimo\Models\Domain object
}, 10, 2);

// After SES DKIM verification (if SES integration is active)
add_action('wu_domain_ses_verified', function($domain) {
    // $domain is a WP_Ultimo\Models\Domain object
});

Logging

Write to your provider-specific log channel using wu_log_add():

wu_log_add('domain-seller-my-registrar', "Registered {$domain_name} successfully", 'info');
wu_log_add('domain-seller-my-registrar', "Registration failed: {$error}", 'error');

Logs appear under Network Admin › Ultimate Multisite › Logs › domain-seller-my-registrar.

The interface​

Optional methods​

Return value convention​

Registering your capability​

Adding credential fields to the wizard​

Hooks for post-registration actions​

Logging​