---
title: "Multiple External Products URLs & Currencies Developer Reference"
description: "Filters, actions, functions and meta keys for customizing Multiple External Products URLs & Currencies with code."
url: "https://wpfactory.com/docs/external-products-developers/"
updated: "2026-09-27"
category: Developers
---

# Multiple External Products URLs & Currencies Developer Reference

This reference covers the filters, actions, functions and meta keys in [Multiple External Products URLs & Currencies for WooCommerce](https://wpfactory.com/item/advanced-external-products-for-woocommerce/) for developers who want to set currencies or link behavior with code. Store owners can configure everything at **WPFactory > Advanced External Products** without code.

## Filters

| Filter | Parameters | Return |
| --- | --- | --- |
| `alg_wc_advanced_external_products_currency` | `$currency` (false), `$product` | A currency code to use for this external product, or `false` to fall back to the All products currency or the store currency. Runs only when the Currency section is enabled. |
| `alg_wc_advanced_external_products_link_single` | `$open` (false) | `true` to open the single page buy button in a new tab. Checked only when the All Products Single option is off. |
| `alg_wc_advanced_external_products_link_loop` | `$open` (false), `$product` | `true` to open the archive buy button in a new tab. Checked only when the All Products Archives option is off. |
| `alg_wc_aep_multiple_urls_single` | `$show` (true) | `false` to stop the extra buy buttons on single pages. |
| `alg_wc_aep_multiple_urls_loop` | `$show` (true) | `false` to stop the extra buy buttons on archives. |

With Pro, the per-product currency is applied at priority 10 on `alg_wc_advanced_external_products_currency` and returns `false` when the product field is **Default**. Hook in at a later priority and respect a non-false value if you want the product field to win.

Example: show USD for external products in the `amazon-us` category, unless a per-product currency is set.

```
add_filter( 'alg_wc_advanced_external_products_currency', function ( $currency, $product ) {
	if ( false === $currency && has_term( 'amazon-us', 'product_cat', $product->get_id() ) ) {
		return 'USD';
	}
	return $currency;
}, 20, 2 );
```

Example: open archive links in a new tab only for products tagged `partner`.

```
add_filter( 'alg_wc_advanced_external_products_link_loop', function ( $open, $product ) {
	return $open || has_term( 'partner', 'product_tag', $product->get_id() );
}, 20, 2 );
```

## Actions

| Action | Parameter | Fires when |
| --- | --- | --- |
| `alg_wc_advanced_external_products_core_loaded` | Core object | All enabled modules are loaded |
| `alg_wc_aep_currency_module_loaded` | Currency module | The Currency section is enabled and loaded |
| `alg_wc_aep_links_module_loaded` | Links module | The Links section is enabled and loaded |
| `alg_wc_aep_multiple_urls_module_loaded` | Multiple URLs module | The Multiple URLs section is enabled and loaded |

## Functions

| Function | Returns |
| --- | --- |
| `alg_wc_advanced_external_products()` | The main plugin instance. Modules are in `->core->modules` (`currency`, `links`, `multiple_urls`). |
| `alg_wc_aep_is_external_product( $product = false )` | `true` if the product (or the current global product) is external. |
| `alg_wc_aep_get_current_product( $product = false )` | The given or current `WC_Product`, or `false`. |

## WooCommerce hooks used

- Currency: `woocommerce_currency` and `woocommerce_currency_symbol` at priority `PHP_INT_MAX`, based on the current post ID.
- Links: `woocommerce_before_add_to_cart_form`, `woocommerce_after_add_to_cart_form` and `woocommerce_loop_add_to_cart_link`.
- Multiple URLs: `woocommerce_after_add_to_cart_form`, `woocommerce_after_shop_loop_item`, `woocommerce_product_add_to_cart_url`, `woocommerce_product_add_to_cart_text` and `woocommerce_product_single_add_to_cart_text`.
- Product fields: `woocommerce_product_options_external` and `save_post_product`.

## Product meta keys

| Meta key | Value |
| --- | --- |
| `_alg_wc_aep_product_urls` | Extra URLs, one per line: `url`, `url|button_text` or `url|button_text|option_label` |
| `_alg_wc_aep_product_urls_default_label` | Dropdown label for the main Product URL (Pro) |
| `_alg_wc_external_product_currency` | Currency code, or empty for Default (Pro) |
| `_alg_wc_external_product_link_new_tab_enabled` | `yes`, `no` or empty (Pro) |
| `_alg_wc_external_product_link_loop_new_tab_enabled` | `yes`, `no` or empty (Pro) |

Need a hand? Our team answers every ticket on the [External Products URLs & Currencies support forum](https://wpfactory.com/support/item/advanced-external-products-for-woocommerce/).

Related articles

- [Multiple External Products URLs & Currencies Settings Reference](https://wpfactory.com/docs/external-products-settings-reference/)
- [Multiple External Products URLs & Currencies Troubleshooting](https://wpfactory.com/docs/external-products-troubleshooting/)
- [Multiple External Products URLs & Currencies: Free vs Pro](https://wpfactory.com/docs/external-products-free-vs-pro/)
- [Getting Started with Multiple External Products URLs & Currencies for WooCommerce](https://wpfactory.com/docs/external-products-getting-started/)
- [How to Add Multiple Buy Links to a WooCommerce External Product](https://wpfactory.com/docs/external-products-multiple-buy-links/)