diff --git a/api/src/main/resources/schema/cron/crondef.json b/api/src/main/resources/schema/cron/crondef.json
new file mode 100644
index 00000000..67bb43c5
--- /dev/null
+++ b/api/src/main/resources/schema/cron/crondef.json
@@ -0,0 +1,18 @@
+{
+  "type": "object",
+  "javaType": "io.serverlessworkflow.api.cron.Cron",
+  "description": "Schedule cron definition",
+  "properties": {
+    "expression": {
+      "type": "string",
+      "description":  "Repeating interval (cron expression) describing when the workflow instance should be created"
+    },
+    "validUntil": {
+      "type": "string",
+      "description":  "Specific date and time (ISO 8601 format) when the cron expression invocation is no longer valid"
+    }
+  },
+  "required": [
+    "expression"
+  ]
+}
\ No newline at end of file
diff --git a/api/src/main/resources/schema/schedule/schedule.json b/api/src/main/resources/schema/schedule/schedule.json
index cbff7bde..d80d9908 100644
--- a/api/src/main/resources/schema/schedule/schedule.json
+++ b/api/src/main/resources/schema/schedule/schedule.json
@@ -8,8 +8,8 @@
       "description":  "Time interval (ISO 8601 format) describing when the workflow starting state is active"
     },
     "cron": {
-      "type": "string",
-      "description":  "Repeating interval (cron expression) describing when the workflow starting state should be triggered"
+      "description":  "Schedule cron definition",
+      "$ref": "../cron/crondef.json"
     },
     "directInvoke": {
       "description": "Define if workflow instances can be created outside of the defined interval/cron",
diff --git a/api/src/test/resources/examples/periodicinboxcheck.json b/api/src/test/resources/examples/periodicinboxcheck.json
index a2b6ecdd..1c5cdfc6 100644
--- a/api/src/test/resources/examples/periodicinboxcheck.json
+++ b/api/src/test/resources/examples/periodicinboxcheck.json
@@ -19,7 +19,9 @@
       "type": "operation",
       "start": {
         "schedule": {
-          "cron": "0 0/15 * * * ?"
+          "cron": {
+            "expression": "0 0/15 * * * ?"
+          }
         }
       },
       "actionMode": "sequential",
diff --git a/api/src/test/resources/examples/periodicinboxcheck.yml b/api/src/test/resources/examples/periodicinboxcheck.yml
index 117b4682..162a29ff 100644
--- a/api/src/test/resources/examples/periodicinboxcheck.yml
+++ b/api/src/test/resources/examples/periodicinboxcheck.yml
@@ -12,7 +12,8 @@ states:
     type: operation
     start:
       schedule:
-        cron: 0 0/15 * * * ?
+        cron:
+          expression: 0 0/15 * * * ?
     actionMode: sequential
     actions:
       - functionRef:
diff --git a/diagram/src/test/resources/examples/periodicinboxcheck.json b/diagram/src/test/resources/examples/periodicinboxcheck.json
index a2b6ecdd..1c5cdfc6 100644
--- a/diagram/src/test/resources/examples/periodicinboxcheck.json
+++ b/diagram/src/test/resources/examples/periodicinboxcheck.json
@@ -19,7 +19,9 @@
       "type": "operation",
       "start": {
         "schedule": {
-          "cron": "0 0/15 * * * ?"
+          "cron": {
+            "expression": "0 0/15 * * * ?"
+          }
         }
       },
       "actionMode": "sequential",
diff --git a/diagram/src/test/resources/examples/periodicinboxcheck.yml b/diagram/src/test/resources/examples/periodicinboxcheck.yml
index 117b4682..162a29ff 100644
--- a/diagram/src/test/resources/examples/periodicinboxcheck.yml
+++ b/diagram/src/test/resources/examples/periodicinboxcheck.yml
@@ -12,7 +12,8 @@ states:
     type: operation
     start:
       schedule:
-        cron: 0 0/15 * * * ?
+        cron:
+          expression: 0 0/15 * * * ?
     actionMode: sequential
     actions:
       - functionRef: