diff --git a/templates/cli/lib/client.js.twig b/templates/cli/lib/client.js.twig
index dc29ae34c..24b96b0e1 100644
--- a/templates/cli/lib/client.js.twig
+++ b/templates/cli/lib/client.js.twig
@@ -91,6 +91,7 @@ class Client {
   }
 
   async call(method, path = "", headers = {}, params = {}) {
+    headers = {...this.headers, ...headers};
     const url = new URL(path, this.endpoint);
 
     let body = undefined;
diff --git a/templates/deno/src/client.ts.twig b/templates/deno/src/client.ts.twig
index 862e23027..087a56a26 100644
--- a/templates/deno/src/client.ts.twig
+++ b/templates/deno/src/client.ts.twig
@@ -62,6 +62,7 @@ export class Client {
     }
 
     async call(method: string, path: string = "", headers: Payload = {}, params: Payload = {}) {
+        headers = {...this.headers, ...headers};
         const url = new URL(path, this.endpoint);
 
         let body: string | FormData | undefined = undefined;
diff --git a/templates/node/lib/client.js.twig b/templates/node/lib/client.js.twig
index 0fe0b7cb3..363518962 100644
--- a/templates/node/lib/client.js.twig
+++ b/templates/node/lib/client.js.twig
@@ -84,6 +84,7 @@ class Client {
     }
       
     async call(method, path = "", headers = {}, params = {}) {
+        headers = {...this.headers, ...headers};
         const url = new URL(path, this.endpoint);
 
         let body = undefined;
diff --git a/tests/Node18Test.php b/tests/Node18Test.php
index e507f1e5f..9df997ba5 100644
--- a/tests/Node18Test.php
+++ b/tests/Node18Test.php
@@ -2,7 +2,7 @@
 
 namespace Tests;
 
-class Node16Test extends Base
+class Node18Test extends Base
 {
     protected string $sdkName = 'node.js';
     protected string $sdkPlatform = 'server';
@@ -15,7 +15,7 @@ class Node16Test extends Base
         'docker run --rm -v $(pwd):/app -w /app/tests/sdks/node node:18-alpine npm install',
     ];
     protected string $command =
-    'docker run --network="mockapi" --rm -v $(pwd):/app -w /app node:16-alpine node tests/languages/node/test.js';
+    'docker run --network="mockapi" --rm -v $(pwd):/app -w /app node:18-alpine node tests/languages/node/test.js';
 
     protected array $expectedOutput = [
         ...Base::FOO_RESPONSES,