diff --git a/planetiler-custommap/planetilerspec.schema.json b/planetiler-custommap/planetilerspec.schema.json
index 1cc463c729..f2e1519d55 100644
--- a/planetiler-custommap/planetilerspec.schema.json
+++ b/planetiler-custommap/planetilerspec.schema.json
@@ -25,11 +25,19 @@
               },
               "geometry": {
                 "description": "Geometry type of the input feature",
-                "type": "string",
-                "enum": [
-                  "polygon",
-                  "line",
-                  "point"
+                "oneOf": [
+                  {
+                    "type": "string",
+                    "enum": [
+                      "polygon",
+                      "line",
+                      "point"
+                    ]
+                  },
+                  {
+                    "type": "string",
+                    "pattern": "^(POLYGON|LINESTRING|POINT) "
+                  }
                 ]
               },
               "tags": {
diff --git a/planetiler-custommap/pom.xml b/planetiler-custommap/pom.xml
index 39a8641768..7860e8180d 100644
--- a/planetiler-custommap/pom.xml
+++ b/planetiler-custommap/pom.xml
@@ -63,6 +63,73 @@
           <skipPublishing>true</skipPublishing>
         </configuration>
       </plugin>
+
+      <plugin>
+        <groupId>com.dataliquid</groupId>
+        <artifactId>json-yaml-validator-maven-plugin</artifactId>
+        <version>1.0.0</version>
+        <executions>
+
+          <execution>
+            <id>validate-positive-yaml</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>validate</goal>
+            </goals>
+            <configuration>
+              <sourceDirectory>.</sourceDirectory>
+              <includes>
+                <include>src/test/resources/validSchema/*.yml</include>
+                <include>src/main/resources/samples/*.yml</include>
+              </includes>
+              <excludes>
+                <exclude>src/main/resources/samples/*.spec.yml</exclude>
+                <!-- shortbread.yml uses aliases which are not supported yet.
+                     See https://github.com/dataliquid/json-yaml-validator-maven-plugin/issues/52
+                -->
+                <exclude>src/main/resources/samples/shortbread.yml</exclude>
+              </excludes>
+              <schemaFile>planetiler.schema.json</schemaFile>
+            </configuration>
+          </execution>
+
+          <execution>
+            <id>validate-positive-spec-yaml</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>validate</goal>
+            </goals>
+            <configuration>
+              <sourceDirectory>.</sourceDirectory>
+              <includes>
+                <include>src/main/resources/samples/*.spec.yml</include>
+              </includes>
+              <schemaFile>planetilerspec.schema.json</schemaFile>
+            </configuration>
+          </execution>
+
+<!-- There is no known way to use the plugin to verify that invalid examples violate the schema
+     See https://github.com/dataliquid/json-yaml-validator-maven-plugin/issues/51
+          <execution>
+            <id>validate-negative-yaml</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>validate</goal>
+            </goals>
+            <configuration>
+              <sourceDirectory>.</sourceDirectory>
+              <includes>
+                <include>src/test/resources/invalidSchema/*.yml</include>
+              </includes>
+              <schemaFile>planetiler.schema.json</schemaFile>
+              <mustError>true</mustError>
+            </configuration>
+          </execution>
+-->    
+
+        </executions>
+      </plugin>
+
     </plugins>
   </build>
 </project>