diff --git a/src/SlackHookHandler.ts b/src/SlackHookHandler.ts
index ce20d81d..10fbd872 100644
--- a/src/SlackHookHandler.ts
+++ b/src/SlackHookHandler.ts
@@ -67,7 +67,7 @@ export class SlackHookHandler extends BaseSlackHandler {
             createServer = (cb) => httpsCreate(tlsOptions, cb);
         }
         return new Promise<void>((resolve, reject) => {
-            const srv = createServer(this._onRequest.bind(this));
+            const srv = createServer(this.onRequest.bind(this));
             srv.once("error", reject);
             srv.listen(port, () => {
                 const protocol = tlsConfig ? "https" : "http";
@@ -85,7 +85,7 @@ export class SlackHookHandler extends BaseSlackHandler {
         }
     }
 
-    public _onRequest(req: IncomingMessage, res: ServerResponse) {
+    private onRequest(req: IncomingMessage, res: ServerResponse) {
         const HTTP_SERVER_ERROR = 500;
         const {method, url } = req;
         if (!method || !url) {
diff --git a/tests/integration/WebhookTest.ts b/tests/integration/WebhookTest.ts
index 141d84ae..60c2602a 100644
--- a/tests/integration/WebhookTest.ts
+++ b/tests/integration/WebhookTest.ts
@@ -73,7 +73,7 @@ describe("WebhookTest", () => {
             });
         });
 
-        harness.hooks._onRequest(req, res);
+        harness.hooks['onRequest'](req, res);
 
         req.emit('end');