diff --git a/playground/vanilla/src/main.ts b/playground/vanilla/src/main.ts
index 73445711..f1c12133 100644
--- a/playground/vanilla/src/main.ts
+++ b/playground/vanilla/src/main.ts
@@ -4,7 +4,10 @@ import './style.css'
 
 const headers = new Headers()
 headers.append('Awiwi', 'Awiwi')
-
+const headers2 = {
+  'Awiwi': 'Awiwi'
+}
+console.log(headers2.constructor.name)
 // 2. Initialize the client with the preview token
 // from your space dashboard at https://app.storyblok.com
 const Storyblok = new StoryblokClient({
diff --git a/src/index.ts b/src/index.ts
index 96d30496..496edac2 100755
--- a/src/index.ts
+++ b/src/index.ts
@@ -105,7 +105,7 @@ class Storyblok {
     headers.set('Accept', 'application/json')
 
     if (config.headers) {
-      const entries = config.headers.entries().toArray()
+      const entries = (config.headers.constructor.name === 'Headers') ? config.headers.entries().toArray() : Object.entries(config.headers)
 
       entries.forEach(([key, value]: [string, string]) => {
         headers.set(key, value)