diff --git a/api.planx.uk/modules/flows/docs.yaml b/api.planx.uk/modules/flows/docs.yaml
index 389ebf4075..d02b1290db 100644
--- a/api.planx.uk/modules/flows/docs.yaml
+++ b/api.planx.uk/modules/flows/docs.yaml
@@ -56,6 +56,25 @@ components:
               type: array
               items:
                 type: string
+    ValidationCheck:
+      type: object
+      properties:
+        title:
+          type: string
+          example: File types
+          required: true
+        status:
+          type: string
+          enum:
+            - Pass
+            - Fail
+            - Warn
+            - Not applicable
+          example: Pass
+        message:
+          type: string
+          example: Your flow has valid file types
+      required: true
   responses:
     CopyFlow:
       content:
@@ -124,19 +143,20 @@ components:
             properties:
               message:
                 type: string
-                required: false
-              description:
-                type: string
-                required: false
+                required: true
               alteredNodes:
                 oneOf:
                   - type: array
                     items:
                       $ref: "#/components/schemas/Node"
                   - type: "null"
-              updatedFlow:
-                $ref: "#/components/schemas/FlowData"
+              validationChecks:
                 required: false
+                oneOf:
+                  - type: array
+                    items:
+                      $ref: "#/components/schemas/ValidationCheck"
+                  - type: "null"
     FlattenData:
       content:
         application/json:
diff --git a/api.planx.uk/modules/flows/validate/service.ts b/api.planx.uk/modules/flows/validate/service.ts
index 231e001687..802f8f5c9e 100644
--- a/api.planx.uk/modules/flows/validate/service.ts
+++ b/api.planx.uk/modules/flows/validate/service.ts
@@ -199,9 +199,8 @@ const validateInviteToPay = (flowGraph: FlowGraph): ValidationResponse => {
 };
 
 const inviteToPayEnabled = (flowGraph: FlowGraph): boolean => {
-  const payNodes = Object.entries(flowGraph).filter(
-    (entry): entry is [string, Node] =>
-      isComponentType(entry, ComponentType.Pay),
+  const payNodes = Object.entries(flowGraph).filter((entry) =>
+    isComponentType(entry, ComponentType.Pay),
   );
   const payNodeStatuses = payNodes.map(
     ([_nodeId, node]) => node?.data?.allowInviteToPay,
@@ -257,9 +256,8 @@ const validateFileTypes = (flowGraph: FlowGraph): ValidationResponse => {
 };
 
 const getFileUploadNodeFns = (flowGraph: FlowGraph): string[] => {
-  const fileUploadNodes = Object.entries(flowGraph).filter(
-    (entry): entry is [string, Node] =>
-      isComponentType(entry, ComponentType.FileUpload),
+  const fileUploadNodes = Object.entries(flowGraph).filter((entry) =>
+    isComponentType(entry, ComponentType.FileUpload),
   );
   return fileUploadNodes.map(([_nodeId, node]) => node.data?.fn as string);
 };
@@ -267,12 +265,12 @@ const getFileUploadNodeFns = (flowGraph: FlowGraph): string[] => {
 const getFileUploadAndLabelNodeFns = (flowGraph: FlowGraph): string[] => {
   // Exclude Upload & Label nodes used in "info-only" mode with a hidden dropzone
   const uploadAndLabelNodes = Object.entries(flowGraph).filter(
-    (entry): entry is [string, Node] =>
+    (entry) =>
       isComponentType(entry, ComponentType.FileUploadAndLabel) &&
       entry[1].data?.hideDropZone !== true,
   );
   const uploadAndLabelFileTypes = uploadAndLabelNodes
-    .map(([_nodeId, node]) => node.data?.fileTypes)
+    .map(([_nodeId, node]: [string, Node]) => node.data?.fileTypes)
     .flat();
   return uploadAndLabelFileTypes?.map((file: any) => file?.fn as string);
 };