diff --git a/README.md b/README.md
index b9d5b36..0f996aa 100644
--- a/README.md
+++ b/README.md
@@ -61,6 +61,7 @@ Copy and paste the following code into a new file in your project:
 // lib/ironOptions.ts
 
 import { IronSessionOptions } from 'iron-session';
+import { Address } from 'wagmi';
 
 if (!process.env.IRON_SESSION_PASSWORD)
   throw new Error('IRON_SESSION_PASSWORD must be set');
@@ -75,7 +76,7 @@ const ironOptions: IronSessionOptions = {
 
 declare module "iron-session" {
   interface IronSessionData {
-    address?: string | undefined;
+    address?: Address | undefined;
     nonce?: string | undefined;
   }
 }
diff --git a/src/api.ts b/src/api.ts
index fae1e76..c10ec24 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -1,5 +1,6 @@
 import type { IncomingMessage, ServerResponse } from 'http';
 import { generateNonce, SiweMessage } from 'siwe';
+import { Address } from 'wagmi';
 import { fromZodError } from 'zod-validation-error';
 import { GetSessionResponse, signInRequestSchema, SignInResponse, SignOutResponse } from './types.js';
 
@@ -55,7 +56,7 @@ export const signIn: RequestHandler<SignInResponse> = async (req, res) => {
   if (!success) return res.status(500).send("Unknown Error");
 
   req.session.nonce = undefined;
-  req.session.address = data.address;
+  req.session.address = data.address as Address;
   await req.session.save();
 
   return res.send("OK");
diff --git a/src/types.ts b/src/types.ts
index 902f820..b1a7dc8 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,9 +1,10 @@
 import "iron-session";
+import { Address } from "wagmi";
 import { z } from "zod";
 
 declare module "iron-session" {
   interface IronSessionData {
-    address?: string | undefined;
+    address?: Address | undefined;
     nonce?: string | undefined;
   }
 }
@@ -30,8 +31,8 @@ export const signInRequestSchema = z.object({
 
 export type GetSessionResponse = {
   authenticated: boolean,
-  address?: string,
-  nonce?: string
+  address?: Address,
+  nonce?: string,
 };
 
 export type SignInRequest = z.infer<typeof signInRequestSchema>;