diff --git a/BTCPayServer/wwwroot/swagger/v1/swagger.template.payment-requests.json b/BTCPayServer/wwwroot/swagger/v1/swagger.template.payment-requests.json
index af3e8cc4d..5427d4dd4 100644
--- a/BTCPayServer/wwwroot/swagger/v1/swagger.template.payment-requests.json
+++ b/BTCPayServer/wwwroot/swagger/v1/swagger.template.payment-requests.json
@@ -326,8 +326,8 @@
                     "currency": {
                         "type": "string",
                         "format": "ISO 4217 Currency code(BTC, EUR, USD, etc)",
-                        "description": "The currency of the payment request",
-                        "nullable": false
+                        "description": "The currency of the payment request. If empty, the store's default currency code will be used.",
+                        "nullable": true
                     },
                     "email": {
                         "type": "string",