diff --git a/lib/middleware.js b/lib/middleware.js
index 4a2f769..6d3d541 100644
--- a/lib/middleware.js
+++ b/lib/middleware.js
@@ -31,7 +31,7 @@ const VERIFIED = Symbol('verified');
  * Returns an instance of bodyParser.json,
  * which also verifies that the request came from Envoy.
  *
- * @param {SignatureVerifierOptions} [options]
+ * @param {SignatureVerifierOptions & {customClientId?: string, customClientSecret?: string}} [options]
  * @returns {connectMiddleware}
  */
 function middleware(options) {
@@ -55,10 +55,13 @@ function middleware(options) {
       try {
         const now = Date.now();
         if (now > threshold) {
+          const hasCustomCredentials = options && options.customClientId && options.customClientSecret;
           const {
             access_token: rawAccessToken,
             expires_in: expiresIn,
-          } = await EnvoyAPI.login();
+          } = hasCustomCredentials 
+            ? await EnvoyAPI.login(options.customClientId, options.customClientSecret)
+            : await EnvoyAPI.login();
           accessToken = rawAccessToken;
           threshold = now + (expiresIn * 1000) - (1000 * 60 * 10);
         }
diff --git a/package.json b/package.json
index 6cfbd4b..d7c893e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@envoy/envoy-integrations-sdk",
-  "version": "1.5.0",
+  "version": "1.5.1-beta.1",
   "description": "",
   "main": "index.js",
   "scripts": {