diff --git a/src/org/kar/archidata/annotation/FormDataOptional.java b/src/org/kar/archidata/annotation/FormDataOptional.java
new file mode 100644
index 0000000..53f2175
--- /dev/null
+++ b/src/org/kar/archidata/annotation/FormDataOptional.java
@@ -0,0 +1,12 @@
+package org.kar.archidata.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target({ ElementType.PARAMETER })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface FormDataOptional {
+
+}
diff --git a/src/org/kar/archidata/externalRestApi/model/ApiModel.java b/src/org/kar/archidata/externalRestApi/model/ApiModel.java
index c95e2a4..180e000 100644
--- a/src/org/kar/archidata/externalRestApi/model/ApiModel.java
+++ b/src/org/kar/archidata/externalRestApi/model/ApiModel.java
@@ -15,6 +15,10 @@ import org.slf4j.LoggerFactory;
 public class ApiModel {
 	static final Logger LOGGER = LoggerFactory.getLogger(ApiModel.class);
 
+	public record OptionalClassModel(
+			List<ClassModel> model,
+			boolean optional) {}
+
 	Class<?> originClass;
 	Method orignMethod;
 
@@ -36,7 +40,7 @@ public class ApiModel {
 	// list of all query (?key...)
 	public final Map<String, List<ClassModel>> queries = new HashMap<>();
 	// when request multi-part, need to separate it.
-	public final Map<String, List<ClassModel>> multiPartParameters = new HashMap<>();
+	public final Map<String, OptionalClassModel> multiPartParameters = new HashMap<>();
 	// model of data available
 	public final List<ClassModel> unnamedElement = new ArrayList<>();
 
@@ -153,6 +157,7 @@ public class ApiModel {
 			final String pathParam = ApiTool.apiAnnotationGetPathParam(parameter);
 			final String queryParam = ApiTool.apiAnnotationGetQueryParam(parameter);
 			final String formDataParam = ApiTool.apiAnnotationGetFormDataParam(parameter);
+			final boolean formDataParamOptional = ApiTool.apiAnnotationGetFormDataOptional(parameter);
 			if (queryParam != null) {
 				if (!this.queries.containsKey(queryParam)) {
 					this.queries.put(queryParam, parameterModel);
@@ -163,7 +168,8 @@ public class ApiModel {
 				}
 			} else if (formDataParam != null) {
 				if (!this.multiPartParameters.containsKey(formDataParam)) {
-					this.multiPartParameters.put(formDataParam, parameterModel);
+					this.multiPartParameters.put(formDataParam,
+							new OptionalClassModel(parameterModel, formDataParamOptional));
 				}
 			} else {
 				this.unnamedElement.addAll(parameterModel);
diff --git a/src/org/kar/archidata/externalRestApi/model/ApiTool.java b/src/org/kar/archidata/externalRestApi/model/ApiTool.java
index 082c0c8..f976c3d 100644
--- a/src/org/kar/archidata/externalRestApi/model/ApiTool.java
+++ b/src/org/kar/archidata/externalRestApi/model/ApiTool.java
@@ -8,6 +8,7 @@ import java.util.List;
 
 import org.glassfish.jersey.media.multipart.FormDataParam;
 import org.kar.archidata.annotation.AsyncType;
+import org.kar.archidata.annotation.FormDataOptional;
 import org.kar.archidata.annotation.TypeScriptProgress;
 
 import io.swagger.v3.oas.annotations.Operation;
@@ -144,6 +145,14 @@ public class ApiTool {
 		return ((QueryParam) annotation[0]).value();
 	}
 
+	public static boolean apiAnnotationGetFormDataOptional(final Parameter element) throws Exception {
+		final Annotation[] annotation = element.getDeclaredAnnotationsByType(FormDataOptional.class);
+		if (annotation.length == 0) {
+			return false;
+		}
+		return true;
+	}
+
 	public static String apiAnnotationGetFormDataParam(final Parameter element) throws Exception {
 		final Annotation[] annotation = element.getDeclaredAnnotationsByType(FormDataParam.class);
 		if (annotation.length == 0) {
diff --git a/src/org/kar/archidata/externalRestApi/typescript/TsApiGeneration.java b/src/org/kar/archidata/externalRestApi/typescript/TsApiGeneration.java
index 2cfaf37..5207907 100644
--- a/src/org/kar/archidata/externalRestApi/typescript/TsApiGeneration.java
+++ b/src/org/kar/archidata/externalRestApi/typescript/TsApiGeneration.java
@@ -17,6 +17,7 @@ import java.util.TreeSet;
 import org.kar.archidata.dataAccess.DataExport;
 import org.kar.archidata.externalRestApi.model.ApiGroupModel;
 import org.kar.archidata.externalRestApi.model.ApiModel;
+import org.kar.archidata.externalRestApi.model.ApiModel.OptionalClassModel;
 import org.kar.archidata.externalRestApi.model.ClassEnumModel;
 import org.kar.archidata.externalRestApi.model.ClassListModel;
 import org.kar.archidata.externalRestApi.model.ClassMapModel;
@@ -229,12 +230,16 @@ public class TsApiGeneration {
 				data.append(",");
 			} else if (interfaceElement.multiPartParameters.size() != 0) {
 				data.append("\n\t\tdata: {");
-				for (final Entry<String, List<ClassModel>> pathEntry : interfaceElement.multiPartParameters
+				for (final Entry<String, OptionalClassModel> pathEntry : interfaceElement.multiPartParameters
 						.entrySet()) {
 					data.append("\n\t\t\t");
 					data.append(pathEntry.getKey());
+					if (pathEntry.getValue().optional()) {
+						data.append("?");
+					}
 					data.append(": ");
-					data.append(generateClassModelsTypescript(pathEntry.getValue(), tsGroup, imports, writeImports));
+					data.append(generateClassModelsTypescript(pathEntry.getValue().model(), tsGroup, imports,
+							writeImports));
 					data.append(",");
 				}
 				data.append("\n\t\t},");