WooCommerce: Check if coupon is valid

I believe the most recent method encouraged by WooCommerce is using the \WC_Discounts Class. Here is an example:

function is_referral_coupon_valid( $coupon_code ) {    $coupon = new \WC_Coupon( $coupon_code );       $discounts = new \WC_Discounts( WC()->cart );    $valid_response = $discounts->is_coupon_valid( $coupon );    if ( is_wp_error( $valid_response ) ) {        return false;    } else {        return true;    }}

It's important to remember doing that inside the wp_loaded hook at least, like this:

add_action( 'wp_loaded', function(){   is_referral_coupon_valid('my-coupon-code');});

UPDATE

Now I believe this simpler method using is_valid() could also work but I haven't tested it myself:

$coupon = new WC_Coupon( 'my-coupon-code' );$coupon->is_valid();

$code = 'test123';$coupon = new WC_Coupon($code);$coupon_post = get_post($coupon->id);$coupon_data = array(    'id' => $coupon->id,    'code' => $coupon->code,    'type' => $coupon->type,    'created_at' => $coupon_post->post_date_gmt,    'updated_at' => $coupon_post->post_modified_gmt,    'amount' => wc_format_decimal($coupon->coupon_amount, 2),    'individual_use' => ( 'yes' === $coupon->individual_use ),    'product_ids' => array_map('absint', (array) $coupon->product_ids),    'exclude_product_ids' => array_map('absint', (array) $coupon->exclude_product_ids),    'usage_limit' => (!empty($coupon->usage_limit) ) ? $coupon->usage_limit : null,    'usage_count' => (int) $coupon->usage_count,    'expiry_date' => (!empty($coupon->expiry_date) ) ? date('Y-m-d', $coupon->expiry_date) : null,    'enable_free_shipping' => $coupon->enable_free_shipping(),    'product_category_ids' => array_map('absint', (array) $coupon->product_categories),    'exclude_product_category_ids' => array_map('absint', (array) $coupon->exclude_product_categories),    'exclude_sale_items' => $coupon->exclude_sale_items(),    'minimum_amount' => wc_format_decimal($coupon->minimum_amount, 2),    'maximum_amount' => wc_format_decimal($coupon->maximum_amount, 2),    'customer_emails' => $coupon->customer_email,    'description' => $coupon_post->post_excerpt,);$usage_left = $coupon_data['usage_limit'] - $coupon_data['usage_count'];if ($usage_left > 0) {    echo 'Coupon Valid';} else {    echo 'Coupon Usage Limit Reached';}

The code is tested and fully functional.

Reference

• WC_API_Coupons::get_coupon( $id, $fields )

You can use this plugin for your purpose.