diff --git a/doc/API.v0.md b/doc/API.v0.md
index 809b916..03fa6de 100644
--- a/doc/API.v0.md
+++ b/doc/API.v0.md
@@ -786,7 +786,7 @@ Proxy response:
 
 ### Create a Lightning Network invoice (called by application)
 
-Returns a LN invoice.  Label must be unique.  Description will be used by your user for payment.  Expiry is in seconds.  If msatoshi is not supplied, will use "any" (ie donation invoice).  callbackUrl is optional.
+Returns a LN invoice.  Label must be unique.  Description will be used by your user for payment.  Expiry is in seconds and optional.  If msatoshi is not supplied, will use "any" (ie donation invoice).  callbackUrl is optional.
 
 ```http
 POST http://cyphernode:8888/ln_create_invoice
diff --git a/doc/openapi/v0/cyphernode-api.yaml b/doc/openapi/v0/cyphernode-api.yaml
index 8418a2d..63f1053 100644
--- a/doc/openapi/v0/cyphernode-api.yaml
+++ b/doc/openapi/v0/cyphernode-api.yaml
@@ -1389,7 +1389,6 @@ paths:
               required:
                 - "label"
                 - "description"
-                - "expiry"
               properties:
                 msatoshi:
                   type: "integer"