diff --git a/build/app/models/post_params_body.go b/build/app/models/post_params_body.go
index 8b5ab29..c5e1c6d 100644
--- a/build/app/models/post_params_body.go
+++ b/build/app/models/post_params_body.go
@@ -12,7 +12,6 @@ import (
 	"github.com/go-openapi/errors"
 	"github.com/go-openapi/strfmt"
 	"github.com/go-openapi/swag"
-	"github.com/go-openapi/validate"
 )
 
 // PostParamsBody post params body
@@ -21,8 +20,7 @@ import (
 type PostParamsBody struct {
 
 	// the filename of the output spreadsheet
-	// Required: true
-	OutFilename *string `json:"out-filename"`
+	OutFilename *string `json:"out-filename,omitempty"`
 
 	// Array of worksheets to create in spreadsheet
 	Sheets []*PostParamsBodySheetsItems `json:"sheets"`
@@ -32,10 +30,6 @@ type PostParamsBody struct {
 func (m *PostParamsBody) Validate(formats strfmt.Registry) error {
 	var res []error
 
-	if err := m.validateOutFilename(formats); err != nil {
-		res = append(res, err)
-	}
-
 	if err := m.validateSheets(formats); err != nil {
 		res = append(res, err)
 	}
@@ -46,15 +40,6 @@ func (m *PostParamsBody) Validate(formats strfmt.Registry) error {
 	return nil
 }
 
-func (m *PostParamsBody) validateOutFilename(formats strfmt.Registry) error {
-
-	if err := validate.Required("out-filename", "body", m.OutFilename); err != nil {
-		return err
-	}
-
-	return nil
-}
-
 func (m *PostParamsBody) validateSheets(formats strfmt.Registry) error {
 	if swag.IsZero(m.Sheets) { // not required
 		return nil
diff --git a/build/app/restapi/embedded_spec.go b/build/app/restapi/embedded_spec.go
index 769c1be..69415d9 100644
--- a/build/app/restapi/embedded_spec.go
+++ b/build/app/restapi/embedded_spec.go
@@ -67,9 +67,6 @@ func init() {
             "in": "body",
             "schema": {
               "type": "object",
-              "required": [
-                "out-filename"
-              ],
               "properties": {
                 "out-filename": {
                   "description": "the filename of the output spreadsheet",
@@ -397,9 +394,6 @@ func init() {
     },
     "postParamsBody": {
       "type": "object",
-      "required": [
-        "out-filename"
-      ],
       "properties": {
         "out-filename": {
           "description": "the filename of the output spreadsheet",
diff --git a/readme.md b/readme.md
index 0b08632..d527f40 100644
--- a/readme.md
+++ b/readme.md
@@ -117,7 +117,7 @@ functions:
 
 | Name | Type | Go type | Required | Default | Description | Example |
 |------|------|---------|:--------:| ------- |-------------|---------|
-| out-filename | string| `string` | ✓ | `"output.xlsx"`| the filename of the output spreadsheet |  |
+| out-filename | string| `string` |  | `"output.xlsx"`| the filename of the output spreadsheet |  |
 | sheets | [][PostParamsBodySheetsItems](#post-params-body-sheets-items)| `[]*PostParamsBodySheetsItems` |  | | Array of worksheets to create in spreadsheet |  |
 
 
diff --git a/swagger.yaml b/swagger.yaml
index 64d260a..32f5269 100644
--- a/swagger.yaml
+++ b/swagger.yaml
@@ -55,8 +55,8 @@ paths:
           in: body
           schema:
             type: object
-            required:
-              - out-filename
+            #required:
+            #  - out-filename
             properties:
               out-filename:
                 type: string