WooCommerce Hook Reference for Developers: Actions & Filters You Actually Use

// Add content before the product title
add_action( 'woocommerce_single_product_summary', 'my_before_product_title', 4 );
function my_before_product_title(): void {
    echo '<span class="product-badge">New Arrival</span>';
}

// Add content after the product price (priority 15 puts it after price at 10, before cart at 30)
add_action( 'woocommerce_single_product_summary', 'my_after_price_content', 15 );
function my_after_price_content(): void {
    global $product;
    if ( $product->is_on_sale() ) {
        echo '<p class="sale-note">Sale ends Sunday.</p>';
    }
}

// Add a tab to the product tabs section
add_filter( 'woocommerce_product_tabs', 'my_custom_product_tab' );
function my_custom_product_tab( array $tabs ): array {
    $tabs['shipping_info'] = [
        'title'    => 'Shipping Info',
        'priority' => 50,
        'callback' => 'my_shipping_tab_content',
    ];
    return $tabs;
}

function my_shipping_tab_content(): void {
    echo '<h2>Shipping Information</h2>';
    echo '<p>Free shipping on orders over $50.</p>';
}

// Modify the "Add to cart" button text
add_filter( 'woocommerce_product_single_add_to_cart_text', 'my_add_to_cart_text' );
function my_add_to_cart_text(): string {
    return 'Buy Now';
}

// Add content before the shop loop
add_action( 'woocommerce_before_shop_loop', 'my_before_shop_content', 20 );
function my_before_shop_content(): void {
    echo '<div class="shop-notice">Summer sale — 20% off everything.</div>';
}

// Add content to each product card in the loop (after the title)
add_action( 'woocommerce_after_shop_loop_item_title', 'my_product_card_content', 15 );
function my_product_card_content(): void {
    global $product;
    echo '<span class="product-sku">SKU: ' . esc_html( $product->get_sku() ) . '</span>';
}

// Change the number of products per row
add_filter( 'loop_shop_columns', 'my_shop_columns' );
function my_shop_columns(): int {
    return 4; // default is 3 or 4 depending on theme
}

// Change products per page
add_filter( 'loop_shop_per_page', 'my_products_per_page' );
function my_products_per_page(): int {
    return 24;
}

// Remove the sorting dropdown above the shop loop
remove_action( 'woocommerce_before_shop_loop', 'woocommerce_catalog_ordering', 30 );

// Add a notice above the cart table
add_action( 'woocommerce_before_cart', 'my_cart_notice' );
function my_cart_notice(): void {
    $threshold = 50;
    $total     = (float) WC()->cart->get_subtotal();
    $remaining = $threshold - $total;

    if ( $remaining > 0 ) {
        wc_print_notice(
            sprintf( 'Add $%.2f more to get free shipping!', $remaining ),
            'notice'
        );
    }
}

// Add a custom fee to the cart
add_action( 'woocommerce_cart_calculate_fees', 'my_handling_fee' );
function my_handling_fee(): void {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) ) {
        return;
    }
    WC()->cart->add_fee( 'Handling Fee', 2.50, true ); // true = taxable
}

// Validate cart item — prevent adding if a condition fails
add_filter( 'woocommerce_add_to_cart_validation', 'my_cart_validation', 10, 3 );
function my_cart_validation( bool $passed, int $product_id, int $quantity ): bool {
    $product = wc_get_product( $product_id );

    if ( $product && $product->get_stock_quantity() < $quantity ) {
        wc_add_notice( 'Not enough stock for that quantity.', 'error' );
        return false;
    }

    return $passed;
}

// Modify cart item data (adds custom data to the cart item)
add_filter( 'woocommerce_add_cart_item_data', 'my_cart_item_data', 10, 2 );
function my_cart_item_data( array $cart_item_data, int $product_id ): array {
    $cart_item_data['custom_note'] = 'Gift wrap requested';
    return $cart_item_data;
}

// Add a custom field to the checkout form
add_action( 'woocommerce_after_order_notes', 'my_checkout_field' );
function my_checkout_field( WC_Checkout $checkout ): void {
    woocommerce_form_field( 'custom_field', [
        'type'        => 'text',
        'class'       => [ 'form-row-wide' ],
        'label'       => 'Delivery instructions',
        'placeholder' => 'Any special instructions for delivery?',
    ], $checkout->get_value( 'custom_field' ) );
}

// Validate the custom field
add_action( 'woocommerce_checkout_process', 'my_checkout_field_validation' );
function my_checkout_field_validation(): void {
    // This field is optional — validate only if filled
    if ( ! empty( $_POST['custom_field'] ) && strlen( $_POST['custom_field'] ) > 500 ) {
        wc_add_notice( 'Delivery instructions must be under 500 characters.', 'error' );
    }
}

// Save the custom field to the order
add_action( 'woocommerce_checkout_update_order_meta', 'my_save_checkout_field' );
function my_save_checkout_field( int $order_id ): void {
    if ( ! empty( $_POST['custom_field'] ) ) {
        update_post_meta(
            $order_id,
            '_custom_field',
            sanitize_textarea_field( $_POST['custom_field'] )
        );
    }
}

// Display the saved field on the order admin screen
add_action( 'woocommerce_admin_order_data_after_billing_address', 'my_display_order_field' );
function my_display_order_field( WC_Order $order ): void {
    $value = get_post_meta( $order->get_id(), '_custom_field', true );
    if ( $value ) {
        echo '<p><strong>Delivery instructions:</strong> ' . esc_html( $value ) . '</p>';
    }
}

// Fires when an order is placed (payment received or COD)
add_action( 'woocommerce_thankyou', 'my_order_placed', 10, 1 );
function my_order_placed( int $order_id ): void {
    $order = wc_get_order( $order_id );
    if ( ! $order ) return;

    // Log or trigger an external system
    error_log( 'New order: ' . $order_id . ' — ' . $order->get_total() );
}

// Fires when order status changes
add_action( 'woocommerce_order_status_changed', 'my_order_status_change', 10, 4 );
function my_order_status_change( int $order_id, string $old_status, string $new_status, WC_Order $order ): void {
    if ( $new_status === 'completed' ) {
        // Award loyalty points, update CRM, etc.
    }
}

// Fires when payment is complete (most reliable hook for order completion)
add_action( 'woocommerce_payment_complete', 'my_payment_complete' );
function my_payment_complete( int $order_id ): void {
    $order = wc_get_order( $order_id );
    // Trigger fulfilment, send to warehouse, etc.
}

// Add a custom column to the orders list
add_filter( 'manage_woocommerce_page_wc-orders_columns', 'my_order_columns' );
function my_order_columns( array $columns ): array {
    $columns['custom_field'] = 'Delivery Notes';
    return $columns;
}

add_action( 'manage_woocommerce_page_wc-orders_custom_column', 'my_order_column_content', 10, 2 );
function my_order_column_content( string $column, WC_Order $order ): void {
    if ( $column === 'custom_field' ) {
        echo esc_html( $order->get_meta( '_custom_field' ) );
    }
}

// Add content to a specific WooCommerce email
add_action( 'woocommerce_email_after_order_table', 'my_email_content', 10, 4 );
function my_email_content( WC_Order $order, bool $sent_to_admin, bool $plain_text, WC_Email $email ): void {
    // Only add to customer emails, not admin notifications
    if ( $sent_to_admin ) return;

    $value = $order->get_meta( '_custom_field' );
    if ( $value ) {
        echo '<p><strong>Delivery instructions:</strong> ' . esc_html( $value ) . '</p>';
    }
}

// Modify email subject
add_filter( 'woocommerce_email_subject_new_order', 'my_email_subject', 10, 2 );
function my_email_subject( string $subject, WC_Order $order ): string {
    return 'New order #' . $order->get_order_number() . ' — ' . get_bloginfo( 'name' );
}

// Add a recipient to the admin new order email
add_filter( 'woocommerce_email_recipient_new_order', 'my_email_recipient', 10, 2 );
function my_email_recipient( string $recipient, WC_Order $order ): string {
    return $recipient . ',warehouse@example.com';
}

// Disable a specific WooCommerce email entirely
add_filter( 'woocommerce_email_enabled_customer_processing_order', '__return_false' );

// Modify product price programmatically
add_filter( 'woocommerce_product_get_price', 'my_dynamic_price', 10, 2 );
add_filter( 'woocommerce_product_get_regular_price', 'my_dynamic_price', 10, 2 );
function my_dynamic_price( string $price, WC_Product $product ): string {
    // Apply 10% discount to a specific category
    if ( has_term( 'members-only', 'product_cat', $product->get_id() ) && is_user_logged_in() ) {
        return (string) ( (float) $price * 0.9 );
    }
    return $price;
}

// Modify the displayed price HTML
add_filter( 'woocommerce_get_price_html', 'my_price_html', 10, 2 );
function my_price_html( string $price, WC_Product $product ): string {
    if ( $product->get_id() === 42 ) {
        return $price . ' <small>(inc. VAT)</small>';
    }
    return $price;
}