Add Login to Your TanStack Start Application

Prerequisites: Before you begin, ensure you have the following installed:

Node.js 20 LTS or newer
npm 10+ or yarn 1.22+ or pnpm 8+

Verify installation: node --version && npm --version

@auth0/auth0-tanstack-start-react is currently in beta (1.0.0-beta.0). The API may change before the stable 1.0 release.

Get Started

This quickstart demonstrates how to add Auth0 authentication to a TanStack Start React application. You’ll build a server-rendered app with login, logout, protected routes, and user profile information using the Auth0 TanStack Start React SDK.

Create a new project

Scaffold a new TanStack Start project for this Quickstart:

npx @tanstack/cli@latest create auth0-tanstack-start --blank --package-manager npm -y

If this is the first time you’ve run @tanstack/cli on your machine, npm asks to confirm installing it: answer y to continue.

Open the project:

cd auth0-tanstack-start

Install the Auth0 TanStack Start SDK

npm install @auth0/auth0-tanstack-start-react

Add Tailwind CSS

Install Tailwind CSS and its Vite plugin:

npm install tailwindcss @tailwindcss/vite

Update vite.config.ts to add the Tailwind plugin and lock the dev server to port 3000:

vite.config.ts

import { defineConfig } from 'vite';
import tailwindcss from '@tailwindcss/vite';
import { tanstackStart } from '@tanstack/react-start/plugin/vite';
import viteReact from '@vitejs/plugin-react';

const config = defineConfig({
  server: { strictPort: true },
  resolve: { tsconfigPaths: true },
  plugins: [tailwindcss(), tanstackStart(), viteReact()],
});

export default config;

Vite fails immediately when you use strictPort: true instead of silently switching ports. Your Auth0 application’s callback URL is locked to port 3000, and since the browser gets redirected to a port nothing is listening on, a silent port change leaves you stuck on a blank page after approving the login screen.

Replace the contents of src/styles.css with:

src/styles.css

@import "tailwindcss";

Create project files

Create the additional files you need for Auth0 integration:

mkdir -p src/components && touch .env src/start.ts src/auth.server.ts src/components/LoginButton.tsx src/components/LogoutButton.tsx src/components/Profile.tsx src/routes/dashboard.tsx

New-Item -ItemType Directory -Force -Path src/components
New-Item -ItemType File -Path .env, src/start.ts, src/auth.server.ts, src/components/LoginButton.tsx, src/components/LogoutButton.tsx, src/components/Profile.tsx, src/routes/dashboard.tsx

Setup your Auth0 App

Next up, you need to create a new app on your Auth0 tenant and add the environment variables to your project.You have three options to set up your Auth0 app: use the Quick Setup tool (recommended), run a CLI command, or configure manually via the Dashboard:

Quick Setup (recommended)
CLI
Dashboard

Create an Auth0 app and copy the pre-filled .env file with the right configuration values.

Run the following command in your project’s root directory to create an Auth0 app and generate an .env file:

# Install Auth0 CLI (if not already installed)
brew tap auth0/auth0-cli && brew install auth0

# Set up Auth0 app and generate an .env file
auth0 qs setup --app --type regular --name "My App" --port 3000

# Install Auth0 CLI (if not already installed)
scoop bucket add auth0 https://github.com/auth0/scoop-auth0-cli.git
scoop install auth0

# Set up Auth0 app and generate .env file
auth0 qs setup --app --type regular --name "My App" --port 3000

This command:

Checks if you’re authenticated (and prompt for login if needed)
Creates an Auth0 Regular Web Application configured for http://localhost:3000
Generates an .env file with AUTH0_DOMAIN, AUTH0_CLIENT_ID, AUTH0_CLIENT_SECRET, AUTH0_SECRET, and APP_BASE_URL

Open the .env file you created in Step 4 and add:

.env

AUTH0_DOMAIN=YOUR_AUTH0_APP_DOMAIN
AUTH0_CLIENT_ID=YOUR_AUTH0_APP_CLIENT_ID
AUTH0_CLIENT_SECRET=YOUR_AUTH0_APP_CLIENT_SECRET
AUTH0_SECRET=YOUR_LONG_RANDOM_SECRET_HERE
APP_BASE_URL=http://localhost:3000

Generate a secure AUTH0_SECRET:

openssl rand -hex 32

Copy the output and replace YOUR_LONG_RANDOM_SECRET_HERE in .env. This must be exactly 64 hexadecimal characters.Then configure your Auth0 application:

Navigate to the Auth0 Dashboard
Select Applications > Applications > Create Application
Enter a name for your app, select Regular Web Application as the app type and select Create
Switch to the Settings tab on the Application Details page
Replace YOUR_AUTH0_APP_DOMAIN, YOUR_AUTH0_APP_CLIENT_ID, and YOUR_AUTH0_APP_CLIENT_SECRET in the .env file with the Domain, Client ID, and Client Secret values from the dashboard

Critical: AUTH0_DOMAIN, AUTH0_CLIENT_ID, AUTH0_CLIENT_SECRET, AUTH0_SECRET, and APP_BASE_URL are read on the server only. Never prefix them with VITE_, or their values will be bundled into client-side JavaScript.

Finally, on the Settings tab of your Application Details page, configure the following URLs:Allowed Callback URLs:

http://localhost:3000/auth/callback

Allowed Logout URLs:

http://localhost:3000

Allowed Web Origins:

http://localhost:3000

Allowed Callback URLs are a critical security measure to ensure users are safely returned to your application after authentication. Without a matching URL, the login process will fail, and end users will be blocked by an Auth0 error page instead of accessing your app.
Allowed Logout URLs are essential for providing a seamless end user experience upon sign out. Without a matching URL, end users are not be redirected back to your application after logout and are instead left on a generic Auth0 page.
Allowed Web Origins is critical for silent authentication. Without it, users are logged out when they refresh the page or return to your app later.

Create the Auth0 server instance

Add the Auth0 server instance to src/auth.server.ts. The Auth0 server instance reads the configuration from the environment variables you just set:

src/auth.server.ts

import { auth0Server } from '@auth0/auth0-tanstack-start-react/server';

export const auth0 = auth0Server();

Add the following to src/start.ts to register the Auth0 request middleware:

src/start.ts

import { createStart } from '@tanstack/react-start';
import { auth0Middleware } from '@auth0/auth0-tanstack-start-react/server/middleware';

export const startInstance = createStart(() => ({
  requestMiddleware: [auth0Middleware()],
}));

Import auth0Middleware from the /server/middleware subpath, not the /server barrel, since start.ts is also compiled into the client bundle.

This middleware automatically mounts the following authentication routes:

/auth/login - Login route
/auth/callback - Callback route
/auth/logout - Logout route
/auth/profile - User profile route
/auth/backchannel-logout - Backchannel logout route

Wire Auth0 into the router

Update src/router.tsx so the router context carries Auth0’s resolved auth state. TanStack Start requires this file to export a function named getRouter:

src/router.tsx

import { createRouter as createTanStackRouter } from '@tanstack/react-router';
import { auth0RouterContext } from '@auth0/auth0-tanstack-start-react/client';
import type { Auth0RouterContext } from '@auth0/auth0-tanstack-start-react/types';
import { routeTree } from './routeTree.gen';

export interface RouterContext {
  auth0: Auth0RouterContext;
}

export function getRouter() {
  const router = createTanStackRouter({
    routeTree,
    scrollRestoration: true,
    defaultPreload: 'intent',
    defaultPreloadStaleTime: 0,
    context: { auth0: auth0RouterContext } satisfies RouterContext,
  });

  return router;
}

declare module '@tanstack/react-router' {
  interface Register {
    router: ReturnType<typeof getRouter>;
  }
}

Update the root route

Update src/routes/__root.tsx to resolve auth state before render and wrap the app in Auth0Provider:

src/routes/__root.tsx

import {
  HeadContent,
  Scripts,
  createRootRouteWithContext,
} from '@tanstack/react-router';
import { Auth0Provider, auth0BeforeLoad } from '@auth0/auth0-tanstack-start-react/client';

import type { RouterContext } from '../router';
import appCss from '../styles.css?url';

export const Route = createRootRouteWithContext<RouterContext>()({
  beforeLoad: auth0BeforeLoad(),
  head: () => ({
    meta: [
      { charSet: 'utf-8' },
      { name: 'viewport', content: 'width=device-width, initial-scale=1' },
      { title: 'Auth0 + TanStack Start' },
    ],
    links: [{ rel: 'stylesheet', href: appCss }],
  }),
  shellComponent: RootDocument,
});

function RootDocument({ children }: { children: React.ReactNode }) {
  return (
    <html lang="en">
      <head>
        <HeadContent />
      </head>
      <body className="antialiased">
        <Auth0Provider>{children}</Auth0Provider>
        <Scripts />
      </body>
    </html>
  );
}

This replaces createRootRoute with createRootRouteWithContext<RouterContext>() so type the route tree as context.auth0.

Create Login, Logout and Profile Components

Add the component code to the files created in Step 4:Then replace the placeholder content of src/routes/index.tsx (the Welcome to TanStack Start page from the scaffold) with:

src/routes/index.tsx

import { createFileRoute } from "@tanstack/react-router";
import { SignedIn, SignedOut } from "@auth0/auth0-tanstack-start-react/client";
import LoginButton from "../components/LoginButton";
import LogoutButton from "../components/LogoutButton";
import Profile from "../components/Profile";

export const Route = createFileRoute("/")({
  component: Home,
});

function Home() {
  return (
    <main className="min-h-screen bg-[#efefef] flex flex-col items-center justify-center gap-4 px-6 py-12">
      <div className="bg-white rounded-[28px] shadow-[0_4px_32px_rgba(0,0,0,0.08)] px-12 py-14 flex flex-col items-center gap-4 w-[360px]">
        <svg width="68" height="68" viewBox="0 0 68 68" fill="none" xmlns="http://www.w3.org/2000/svg" className="mb-1">
          <g filter="url(#filter0_di)">
            <rect x="2" y="2" width="64" height="64" rx="16" fill="url(#paint0_linear)"/>
            <rect x="2.5" y="2.5" width="63" height="63" rx="15.5" stroke="#252525"/>
            <path d="M34.0002 18C25.1572 18 18 25.1669 18 34C18 42.8432 25.1672 50 34.0002 50C42.8333 50 50 42.8331 50 34C50 25.1669 42.8433 18 34.0002 18ZM43.9172 43.8971C43.9172 43.9071 43.9069 43.9072 43.9069 43.9172C43.9069 43.9172 43.8969 43.9272 43.8868 43.9272C43.144 44.65 41.9796 44.7303 41.0662 44.2585L40.0228 43.7265C36.2487 41.7792 31.7619 41.7792 27.9777 43.7265L26.9338 44.2585C26.0103 44.7303 24.8459 44.65 24.1132 43.9272C24.1132 43.9272 24.1031 43.9172 24.0931 43.9172C24.0931 43.9172 24.0828 43.9071 24.0828 43.8971C23.3601 43.1543 23.2797 41.9899 23.7515 41.0765L24.2837 40.0326C26.231 36.2585 26.231 31.7717 24.2837 27.9975L23.7515 26.9536C23.2797 26.0302 23.3601 24.8657 24.0828 24.133C24.0828 24.1229 24.0931 24.123 24.0931 24.123C24.0931 24.123 24.1031 24.1129 24.1132 24.1129C24.856 23.3902 26.0204 23.3099 26.9338 23.7817L27.9777 24.3137C31.7518 26.261 36.2386 26.261 40.0228 24.3137L41.0662 23.7817C41.9897 23.3099 43.1541 23.3902 43.8868 24.1129C43.8868 24.1129 43.8969 24.123 43.9069 24.123L43.9172 24.133C44.6399 24.8758 44.7203 26.0402 44.2485 26.9536L43.7163 27.9975C41.769 31.7717 41.769 36.2585 43.7163 40.0326L44.2485 41.0765C44.7203 41.9899 44.6499 43.1543 43.9172 43.8971Z" fill="white"/>
          </g>
          <defs>
            <filter id="filter0_di" x="0" y="0" width="68" height="68" filterUnits="userSpaceOnUse" colorInterpolationFilters="sRGB">
              <feFlood floodOpacity="0" result="BackgroundImageFix"/>
              <feColorMatrix in="SourceAlpha" type="matrix" values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 0" result="hardAlpha"/>
              <feMorphology radius="2" operator="dilate" in="SourceAlpha" result="effect1_dropShadow"/>
              <feOffset/>
              <feComposite in2="hardAlpha" operator="out"/>
              <feColorMatrix type="matrix" values="0 0 0 0 0.117647 0 0 0 0 0.129412 0 0 0 0 0.164706 0 0 0 0.12 0"/>
              <feBlend mode="normal" in2="BackgroundImageFix" result="effect1_dropShadow"/>
              <feBlend mode="normal" in="SourceGraphic" in2="effect1_dropShadow" result="shape"/>
              <feColorMatrix in="SourceAlpha" type="matrix" values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 0" result="hardAlpha"/>
              <feOffset dy="-1"/>
              <feGaussianBlur stdDeviation="0.5"/>
              <feComposite in2="hardAlpha" operator="arithmetic" k2="-1" k3="1"/>
              <feColorMatrix type="matrix" values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.04 0"/>
              <feBlend mode="normal" in2="shape" result="effect2_innerShadow"/>
            </filter>
            <linearGradient id="paint0_linear" x1="34" y1="2" x2="34" y2="66" gradientUnits="userSpaceOnUse">
              <stop/>
              <stop offset="1" stopColor="#677190"/>
            </linearGradient>
          </defs>
        </svg>

        <SignedIn>
          <h1 className="text-[17px] font-bold text-gray-900 tracking-tight">Your account</h1>
          <div className="w-full h-px bg-gray-100" />
          <Profile />
          <LogoutButton />
        </SignedIn>
        <SignedOut>
          <h1 className="text-[17px] font-bold text-gray-900 tracking-tight">Welcome to Auth0 + TanStack Start</h1>
          <p className="text-[13px] text-gray-400 text-center leading-relaxed -mt-2">
            Get started by logging in to your account
          </p>
          <div className="h-3" />
          <LoginButton />
        </SignedOut>
      </div>

      <div className="flex items-center gap-1.5 text-[11px] text-gray-400">
        <span>Powered by</span>
        <img
          src="https://cdn.auth0.com/quantum-assets/dist/latest/logos/auth0/auth0-lockup-en-onlight.svg"
          alt="Auth0"
          className="h-3 opacity-40"
        />
      </div>
    </main>
  );
}

useLogin and useLogout perform a full browser navigation rather than a client-side router transition because /auth/* is handled by the server middleware and the session cookie requires a page reload to take effect.

Protect a route

Add a protected /dashboard route to src/routes/dashboard.tsx using the requireAuth guard. It redirects unauthenticated users to /auth/login on the server before any HTML is sent to the browser:

src/routes/dashboard.tsx

import { createFileRoute } from "@tanstack/react-router";
import { requireAuth, useUser } from "@auth0/auth0-tanstack-start-react/client";
import LogoutButton from "../components/LogoutButton";
import Profile from "../components/Profile";

export const Route = createFileRoute("/dashboard")({
  beforeLoad: requireAuth({ returnTo: "/dashboard" }),
  component: Dashboard,
});

function Dashboard() {
  const user = useUser();

  return (
    <main className="min-h-screen bg-[#efefef] flex flex-col items-center justify-center gap-4 px-6 py-12">
      <div className="bg-white rounded-[28px] shadow-[0_4px_32px_rgba(0,0,0,0.08)] px-12 py-14 flex flex-col items-center gap-4 w-[360px]">
        <h1 className="text-[17px] font-bold text-gray-900 tracking-tight">Welcome, {user?.name}!</h1>
        <div className="w-full h-px bg-gray-100" />
        <Profile />
        <LogoutButton />
      </div>
    </main>
  );
}

Run your app

npm run dev

Your app is available at http://localhost:3000.

CheckpointYou should now have a fully functional Auth0 login page running on your localhost

Quickstarts

Auth0 Overview

Configure Auth0

Applications

Add Login to Your TanStack Start Application

Get Started

​Get Started

Get Started