diff --git a/modules/openapi-generator/src/main/resources/typescript-fetch/runtime.mustache b/modules/openapi-generator/src/main/resources/typescript-fetch/runtime.mustache
index 6f8038f5bdf2..cb7f747ea45f 100644
--- a/modules/openapi-generator/src/main/resources/typescript-fetch/runtime.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-fetch/runtime.mustache
@@ -3,6 +3,8 @@
 
 export const BASE_PATH = "{{{basePath}}}".replace(/\/+$/, "");
 
+const isBlob = (value: any) => typeof Blob !== 'undefined' && value instanceof Blob;
+
 /**
  * This is the base class for all generated API classes.
  */
@@ -47,7 +49,9 @@ export class BaseAPI {
             // do not handle correctly sometimes.
             url += '?' + querystring(context.query);
         }
-        const body = context.body instanceof FormData ? context.body : JSON.stringify(context.body);
+        const body = (context.body instanceof FormData || isBlob(context.body))
+	    ? context.body
+	    : JSON.stringify(context.body);
         const init = {
             method: context.method,
             headers: context.headers,
diff --git a/samples/client/petstore/typescript-fetch/builds/default/models/InlineObject.ts b/samples/client/petstore/typescript-fetch/builds/default/models/InlineObject.ts
new file mode 100644
index 000000000000..2998b1463ce5
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/default/models/InlineObject.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject
+ */
+export interface InlineObject {
+    /**
+     * Updated name of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    name?: string;
+    /**
+     * Updated status of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    status?: string;
+}
+
+export function InlineObjectFromJSON(json: any): InlineObject {
+    return {
+        'name': !exists(json, 'name') ? undefined : json['name'],
+        'status': !exists(json, 'status') ? undefined : json['status'],
+    };
+}
+
+export function InlineObjectToJSON(value?: InlineObject): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'name': value.name,
+        'status': value.status,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/default/models/InlineObject1.ts b/samples/client/petstore/typescript-fetch/builds/default/models/InlineObject1.ts
new file mode 100644
index 000000000000..4cd90b137959
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/default/models/InlineObject1.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject1
+ */
+export interface InlineObject1 {
+    /**
+     * Additional data to pass to server
+     * @type {string}
+     * @memberof InlineObject1
+     */
+    additionalMetadata?: string;
+    /**
+     * file to upload
+     * @type {Blob}
+     * @memberof InlineObject1
+     */
+    file?: Blob;
+}
+
+export function InlineObject1FromJSON(json: any): InlineObject1 {
+    return {
+        'additionalMetadata': !exists(json, 'additionalMetadata') ? undefined : json['additionalMetadata'],
+        'file': !exists(json, 'file') ? undefined : json['file'],
+    };
+}
+
+export function InlineObject1ToJSON(value?: InlineObject1): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'additionalMetadata': value.additionalMetadata,
+        'file': value.file,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/default/runtime.ts b/samples/client/petstore/typescript-fetch/builds/default/runtime.ts
index 67a45b169fde..5b07f8111862 100644
--- a/samples/client/petstore/typescript-fetch/builds/default/runtime.ts
+++ b/samples/client/petstore/typescript-fetch/builds/default/runtime.ts
@@ -14,6 +14,8 @@
 
 export const BASE_PATH = "http://petstore.swagger.io/v2".replace(/\/+$/, "");
 
+const isBlob = (value: any) => typeof Blob !== 'undefined' && value instanceof Blob;
+
 /**
  * This is the base class for all generated API classes.
  */
@@ -58,7 +60,9 @@ export class BaseAPI {
             // do not handle correctly sometimes.
             url += '?' + querystring(context.query);
         }
-        const body = context.body instanceof FormData ? context.body : JSON.stringify(context.body);
+        const body = (context.body instanceof FormData || isBlob(context.body))
+	    ? context.body
+	    : JSON.stringify(context.body);
         const init = {
             method: context.method,
             headers: context.headers,
diff --git a/samples/client/petstore/typescript-fetch/builds/es6-target/models/InlineObject.ts b/samples/client/petstore/typescript-fetch/builds/es6-target/models/InlineObject.ts
new file mode 100644
index 000000000000..2998b1463ce5
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/es6-target/models/InlineObject.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject
+ */
+export interface InlineObject {
+    /**
+     * Updated name of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    name?: string;
+    /**
+     * Updated status of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    status?: string;
+}
+
+export function InlineObjectFromJSON(json: any): InlineObject {
+    return {
+        'name': !exists(json, 'name') ? undefined : json['name'],
+        'status': !exists(json, 'status') ? undefined : json['status'],
+    };
+}
+
+export function InlineObjectToJSON(value?: InlineObject): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'name': value.name,
+        'status': value.status,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/es6-target/models/InlineObject1.ts b/samples/client/petstore/typescript-fetch/builds/es6-target/models/InlineObject1.ts
new file mode 100644
index 000000000000..4cd90b137959
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/es6-target/models/InlineObject1.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject1
+ */
+export interface InlineObject1 {
+    /**
+     * Additional data to pass to server
+     * @type {string}
+     * @memberof InlineObject1
+     */
+    additionalMetadata?: string;
+    /**
+     * file to upload
+     * @type {Blob}
+     * @memberof InlineObject1
+     */
+    file?: Blob;
+}
+
+export function InlineObject1FromJSON(json: any): InlineObject1 {
+    return {
+        'additionalMetadata': !exists(json, 'additionalMetadata') ? undefined : json['additionalMetadata'],
+        'file': !exists(json, 'file') ? undefined : json['file'],
+    };
+}
+
+export function InlineObject1ToJSON(value?: InlineObject1): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'additionalMetadata': value.additionalMetadata,
+        'file': value.file,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/es6-target/runtime.ts b/samples/client/petstore/typescript-fetch/builds/es6-target/runtime.ts
index 67a45b169fde..5b07f8111862 100644
--- a/samples/client/petstore/typescript-fetch/builds/es6-target/runtime.ts
+++ b/samples/client/petstore/typescript-fetch/builds/es6-target/runtime.ts
@@ -14,6 +14,8 @@
 
 export const BASE_PATH = "http://petstore.swagger.io/v2".replace(/\/+$/, "");
 
+const isBlob = (value: any) => typeof Blob !== 'undefined' && value instanceof Blob;
+
 /**
  * This is the base class for all generated API classes.
  */
@@ -58,7 +60,9 @@ export class BaseAPI {
             // do not handle correctly sometimes.
             url += '?' + querystring(context.query);
         }
-        const body = context.body instanceof FormData ? context.body : JSON.stringify(context.body);
+        const body = (context.body instanceof FormData || isBlob(context.body))
+	    ? context.body
+	    : JSON.stringify(context.body);
         const init = {
             method: context.method,
             headers: context.headers,
diff --git a/samples/client/petstore/typescript-fetch/builds/with-interfaces/models/InlineObject.ts b/samples/client/petstore/typescript-fetch/builds/with-interfaces/models/InlineObject.ts
new file mode 100644
index 000000000000..2998b1463ce5
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/with-interfaces/models/InlineObject.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject
+ */
+export interface InlineObject {
+    /**
+     * Updated name of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    name?: string;
+    /**
+     * Updated status of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    status?: string;
+}
+
+export function InlineObjectFromJSON(json: any): InlineObject {
+    return {
+        'name': !exists(json, 'name') ? undefined : json['name'],
+        'status': !exists(json, 'status') ? undefined : json['status'],
+    };
+}
+
+export function InlineObjectToJSON(value?: InlineObject): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'name': value.name,
+        'status': value.status,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/with-interfaces/models/InlineObject1.ts b/samples/client/petstore/typescript-fetch/builds/with-interfaces/models/InlineObject1.ts
new file mode 100644
index 000000000000..4cd90b137959
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/with-interfaces/models/InlineObject1.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject1
+ */
+export interface InlineObject1 {
+    /**
+     * Additional data to pass to server
+     * @type {string}
+     * @memberof InlineObject1
+     */
+    additionalMetadata?: string;
+    /**
+     * file to upload
+     * @type {Blob}
+     * @memberof InlineObject1
+     */
+    file?: Blob;
+}
+
+export function InlineObject1FromJSON(json: any): InlineObject1 {
+    return {
+        'additionalMetadata': !exists(json, 'additionalMetadata') ? undefined : json['additionalMetadata'],
+        'file': !exists(json, 'file') ? undefined : json['file'],
+    };
+}
+
+export function InlineObject1ToJSON(value?: InlineObject1): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'additionalMetadata': value.additionalMetadata,
+        'file': value.file,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/with-interfaces/runtime.ts b/samples/client/petstore/typescript-fetch/builds/with-interfaces/runtime.ts
index 67a45b169fde..5b07f8111862 100644
--- a/samples/client/petstore/typescript-fetch/builds/with-interfaces/runtime.ts
+++ b/samples/client/petstore/typescript-fetch/builds/with-interfaces/runtime.ts
@@ -14,6 +14,8 @@
 
 export const BASE_PATH = "http://petstore.swagger.io/v2".replace(/\/+$/, "");
 
+const isBlob = (value: any) => typeof Blob !== 'undefined' && value instanceof Blob;
+
 /**
  * This is the base class for all generated API classes.
  */
@@ -58,7 +60,9 @@ export class BaseAPI {
             // do not handle correctly sometimes.
             url += '?' + querystring(context.query);
         }
-        const body = context.body instanceof FormData ? context.body : JSON.stringify(context.body);
+        const body = (context.body instanceof FormData || isBlob(context.body))
+	    ? context.body
+	    : JSON.stringify(context.body);
         const init = {
             method: context.method,
             headers: context.headers,
diff --git a/samples/client/petstore/typescript-fetch/builds/with-npm-version/models/InlineObject.ts b/samples/client/petstore/typescript-fetch/builds/with-npm-version/models/InlineObject.ts
new file mode 100644
index 000000000000..2998b1463ce5
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/with-npm-version/models/InlineObject.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject
+ */
+export interface InlineObject {
+    /**
+     * Updated name of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    name?: string;
+    /**
+     * Updated status of the pet
+     * @type {string}
+     * @memberof InlineObject
+     */
+    status?: string;
+}
+
+export function InlineObjectFromJSON(json: any): InlineObject {
+    return {
+        'name': !exists(json, 'name') ? undefined : json['name'],
+        'status': !exists(json, 'status') ? undefined : json['status'],
+    };
+}
+
+export function InlineObjectToJSON(value?: InlineObject): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'name': value.name,
+        'status': value.status,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/with-npm-version/models/InlineObject1.ts b/samples/client/petstore/typescript-fetch/builds/with-npm-version/models/InlineObject1.ts
new file mode 100644
index 000000000000..4cd90b137959
--- /dev/null
+++ b/samples/client/petstore/typescript-fetch/builds/with-npm-version/models/InlineObject1.ts
@@ -0,0 +1,52 @@
+// tslint:disable
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+import { exists, mapValues } from '../runtime';
+/**
+ * 
+ * @export
+ * @interface InlineObject1
+ */
+export interface InlineObject1 {
+    /**
+     * Additional data to pass to server
+     * @type {string}
+     * @memberof InlineObject1
+     */
+    additionalMetadata?: string;
+    /**
+     * file to upload
+     * @type {Blob}
+     * @memberof InlineObject1
+     */
+    file?: Blob;
+}
+
+export function InlineObject1FromJSON(json: any): InlineObject1 {
+    return {
+        'additionalMetadata': !exists(json, 'additionalMetadata') ? undefined : json['additionalMetadata'],
+        'file': !exists(json, 'file') ? undefined : json['file'],
+    };
+}
+
+export function InlineObject1ToJSON(value?: InlineObject1): any {
+    if (value === undefined) {
+        return undefined;
+    }
+    return {
+        'additionalMetadata': value.additionalMetadata,
+        'file': value.file,
+    };
+}
+
+
diff --git a/samples/client/petstore/typescript-fetch/builds/with-npm-version/runtime.ts b/samples/client/petstore/typescript-fetch/builds/with-npm-version/runtime.ts
index 67a45b169fde..5b07f8111862 100644
--- a/samples/client/petstore/typescript-fetch/builds/with-npm-version/runtime.ts
+++ b/samples/client/petstore/typescript-fetch/builds/with-npm-version/runtime.ts
@@ -14,6 +14,8 @@
 
 export const BASE_PATH = "http://petstore.swagger.io/v2".replace(/\/+$/, "");
 
+const isBlob = (value: any) => typeof Blob !== 'undefined' && value instanceof Blob;
+
 /**
  * This is the base class for all generated API classes.
  */
@@ -58,7 +60,9 @@ export class BaseAPI {
             // do not handle correctly sometimes.
             url += '?' + querystring(context.query);
         }
-        const body = context.body instanceof FormData ? context.body : JSON.stringify(context.body);
+        const body = (context.body instanceof FormData || isBlob(context.body))
+	    ? context.body
+	    : JSON.stringify(context.body);
         const init = {
             method: context.method,
             headers: context.headers,