diff --git a/json/feature-with-id.json b/json/feature-with-id.json
new file mode 100644
index 0000000..1ecf49b
--- /dev/null
+++ b/json/feature-with-id.json
@@ -0,0 +1,15 @@
+{
+  "id": 12345,
+  "type": "Feature",
+  "geometry": {
+    "type": "Point",
+    "coordinates": [
+      125.6,
+      10.1
+    ]
+  },
+  "properties": {
+    "name": "Dinagat Islands"
+  },
+  "something": 234
+}
diff --git a/json/feature-with-invalid-id.json b/json/feature-with-invalid-id.json
new file mode 100644
index 0000000..afcc121
--- /dev/null
+++ b/json/feature-with-invalid-id.json
@@ -0,0 +1,15 @@
+{
+  "id": "12345",
+  "type": "Feature",
+  "geometry": {
+    "type": "Point",
+    "coordinates": [
+      125.6,
+      10.1
+    ]
+  },
+  "properties": {
+    "name": "Dinagat Islands"
+  },
+  "something": 234
+}