curl --location -g --request GET 'http:///V1/coupons/'
{
"code": "string",
"coupon_id": 0,
"created_at": "string",
"expiration_date": "string",
"extension_attributes": {},
"is_primary": true,
"rule_id": 0,
"times_used": 0,
"type": 0,
"usage_limit": 0,
"usage_per_customer": 0
}