diff --git a/src/App.tsx b/src/App.tsx
index ed2333f..22575ed 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -13,14 +13,10 @@ import { BuyReturn } from "./pages/BuyReturn.tsx";
 import { Grid, Paper } from "@mui/material";
 
 function App() {
-  const locallyStoredUserId = window.localStorage.getItem("paysplit-user-id");
-  const locallyStoredUserIdAsNumber = locallyStoredUserId
-    ? parseInt(locallyStoredUserId)
-    : null;
-  const [userId, setUserId] = useState<number | null>(
-    locallyStoredUserIdAsNumber,
+  const [userId, setUserId] = useState<string | null>(
+    window.localStorage.getItem("paysplit-user-id")
   );
-  const storeUserId = (id: number) => {
+  const storeUserId = (id: string) => {
     window.localStorage.setItem("paysplit-user-id", id.toString());
     setUserId(id);
   };
diff --git a/src/api/client.ts b/src/api/client.ts
index e3e22cf..4ed6064 100644
--- a/src/api/client.ts
+++ b/src/api/client.ts
@@ -1,7 +1,7 @@
 import axios, { type AxiosResponse } from "axios";
 
 interface AccessResponse {
-  userId: number;
+  userId: string;
 }
 
 export const login = (name: string, password: string) =>
@@ -16,12 +16,12 @@ export const registerUser = (name: string, password: string) =>
     password,
   }) as Promise<AxiosResponse<AccessResponse, unknown, {}>>;
 
-export const startBuyFlow = (userId: number, quantity: number) =>
+export const startBuyFlow = (userId: string, quantity: number) =>
   axios.post("/buy/start", { userId, quantity }) as Promise<
     AxiosResponse<{ url: string }, unknown, {}>
   >;
 
-export const completeBuyFlow = (userId: number) =>
+export const completeBuyFlow = (userId: string) =>
   axios.post("/buy/complete", { userId }) as Promise<
     AxiosResponse<{ url: string }, unknown, {}>
   >;
diff --git a/src/context/logged-in-page-context.ts b/src/context/logged-in-page-context.ts
index d8d9bc8..b3f590b 100644
--- a/src/context/logged-in-page-context.ts
+++ b/src/context/logged-in-page-context.ts
@@ -1,7 +1,7 @@
 import { createContext } from "react";
 
 interface LoggedInPageContextProps {
-  userId: number;
+  userId: string;
 }
 
 export const LoggedInPageContext =
diff --git a/src/context/pre-login-page-context.ts b/src/context/pre-login-page-context.ts
index 089681d..353280b 100644
--- a/src/context/pre-login-page-context.ts
+++ b/src/context/pre-login-page-context.ts
@@ -1,7 +1,7 @@
 import { createContext } from "react";
 
 interface PreLoginPageContextProps {
-  setUserId: (id: number) => void;
+  setUserId: (id: string) => void;
 }
 
 export const PreLoginPageContext =