diff --git a/src/org/zaproxy/zap/extension/api/API.java b/src/org/zaproxy/zap/extension/api/API.java
index <HASH>..<HASH> 100644
--- a/src/org/zaproxy/zap/extension/api/API.java
+++ b/src/org/zaproxy/zap/extension/api/API.java
@@ -303,7 +303,7 @@ public class API {
 							List<String> mandatoryParams = other.getMandatoryParamNames();
 							if (mandatoryParams != null) {
 								for (String param : mandatoryParams) {
-									if (params.getString(param) == null || params.getString(param).length() == 0) {
+									if (!params.has(param) || params.getString(param).length() == 0) {
 										throw new ApiException(ApiException.Type.MISSING_PARAMETER, param);
 									}
 								}
Issue <I> - JSONException while calling an API "other" without the required parameter(s)

Changed to check if the parameter exists (instead of getting it).