diff --git a/src/main/java/org/icgc/argo/workflow_management/controller/model/RunsRequest.java b/src/main/java/org/icgc/argo/workflow_management/controller/model/RunsRequest.java
index 9ac20ae..6025bff 100644
--- a/src/main/java/org/icgc/argo/workflow_management/controller/model/RunsRequest.java
+++ b/src/main/java/org/icgc/argo/workflow_management/controller/model/RunsRequest.java
@@ -3,6 +3,8 @@
 import com.fasterxml.jackson.databind.PropertyNamingStrategy;
 import com.fasterxml.jackson.databind.annotation.JsonNaming;
 import io.swagger.annotations.ApiModel;
+
+import java.util.HashMap;
 import java.util.Map;
 import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.NotNull;
@@ -19,10 +21,9 @@ public class RunsRequest {
   @NotBlank(message = "workflow_url is a required field!")
   private String workflowUrl;
 
-  @NotNull(message = "workflow_params is a required field!")
-  private Map<String, Object> workflowParams;
+  private Map<String, Object> workflowParams = new HashMap<String, Object>();
+  private WorkflowEngineParams workflowEngineParams = new WorkflowEngineParams();
 
-  private WorkflowEngineParams workflowEngineParams;
   private Map<String, Object> workflowType;
   private String[] workflowTypeVersion;
   private Map<String, Object> tags;
diff --git a/src/test/java/org/icgc/argo/workflow_management/ErrorHandlingTests.java b/src/test/java/org/icgc/argo/workflow_management/ErrorHandlingTests.java
index d3afce6..14798f2 100644
--- a/src/test/java/org/icgc/argo/workflow_management/ErrorHandlingTests.java
+++ b/src/test/java/org/icgc/argo/workflow_management/ErrorHandlingTests.java
@@ -176,9 +176,7 @@ public void testInvalidRunsRequest() {
         .jsonPath("$.status_code")
         .isEqualTo(BAD_REQUEST.value())
         .jsonPath("$.msg")
-        .value(containsString("workflow_url is a required field!"))
-        .jsonPath("$.msg")
-        .value(containsString("workflow_params is a required field!"));
+        .value(containsString("workflow_url is a required field!"));
 
     // Assert a request with only the workflowParams field defined returns a BAD_REQUEST
     val reqWorkflowUrlUndefined = new RunsRequest();