diff --git a/keyserver/src/responders/link-responders.js b/keyserver/src/responders/link-responders.js
--- a/keyserver/src/responders/link-responders.js
+++ b/keyserver/src/responders/link-responders.js
@@ -42,7 +42,7 @@
 
 async function inviteLinkVerificationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<InviteLinkVerificationResponse> {
   const request = await validateInput(
     viewer,