diff --git a/open-sse/executors/default.js b/open-sse/executors/default.js
index 1af130c2..db5a290a 100644
--- a/open-sse/executors/default.js
+++ b/open-sse/executors/default.js
@@ -157,6 +157,12 @@ export class DefaultExecutor extends BaseExecutor {
       const baseUrl = credentials?.providerSpecificData?.baseUrl || "";
       const isOfficialAnthropic = baseUrl === "" || baseUrl.includes("api.anthropic.com");
       if (!isOfficialAnthropic) {
+        // Some third-party Anthropic-compatible gateways require Bearer auth in
+        // addition to x-api-key. Send both (x-api-key already set above) so
+        // gateways that read either header succeed.
+        if (credentials.apiKey && !headers["Authorization"]) {
+          headers["Authorization"] = `Bearer ${credentials.apiKey}`;
+        }
         delete headers["anthropic-dangerous-direct-browser-access"];
         delete headers["Anthropic-Dangerous-Direct-Browser-Access"];
         delete headers["x-app"];