Next.js Quickstart

Get Started using the Keverd Next.js SDK

Overview

In this 5-minute quickstart, you’ll add Keverd to a Next.js app and get:

Persistent device IDs that survive incognito, VPNs, and browser clears
Real-time risk scores for every user action
Automatic fraud detection with minimal setup

No backend setup required for the frontend integration. Keverd works out-of-the-box with your existing Next.js app.

Prerequisites

Node.js 18+ and npm
Your Favorite Code Editor
A Next.js app (new or existing, App Router or Pages Router)
5 minutes of your time

This quickstart covers the frontend setup only. You’ll need a backend server to receive and process device identification events for full fraud detection. Check out one of the backend quickstarts after completing this.

Step 1: Get Your API Key

Sign up for a free Keverd account at dashboard.keverd.com/request-access
Navigate to Settings → API Keys
Copy your Public API Key (starts with pk_live_)

Step 2: Install the SDK

npm install @keverdjs/react

We use the @keverdjs/react package for Next.js. It is fully compatible with both App Router and Pages Router.

Step 3: Wrap Your App with KeverdProvider

Choose your router below. The provider prepares Keverd but does not trigger API calls yet.

App Router

Create a client component wrapper:

// app/components/KeverdWrapper.jsx
'use client';

import { KeverdProvider } from '@keverdjs/react';

export function KeverdWrapper({ children }) {
  return (
    <KeverdProvider apiKey="pk_live_your_api_key_here">
      {children}
    </KeverdProvider>
  );
}

Then use it in your root layout:

// app/layout.jsx
import { KeverdWrapper } from './components/KeverdWrapper';

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body>
        <KeverdWrapper>
          {children}
        </KeverdWrapper>
      </body>
    </html>
  );
}

Pages Router

// pages/_app.jsx
import { KeverdProvider } from '@keverdjs/react';

export default function MyApp({ Component, pageProps }) {
  return (
    <KeverdProvider apiKey="pk_live_your_api_key_here">
      <Component {...pageProps} />
    </KeverdProvider>
  );
}

Step 4: Initialize Fingerprinting

Keverd only starts collecting device data and making API calls when a component calls useKeverd(). This is intentional — it gives you control over when fingerprinting happens (e.g., on login, checkout, or page load).

useKeverd() must be called inside a Client Component ('use client' in App Router). It cannot be used in Server Components.

Basic usage — trigger on component mount:

// app/checkout/page.jsx (App Router)
'use client';

import { useKeverd } from '@keverdjs/react';

export default function CheckoutPage() {
  const { deviceId, riskScore, isLoading, error } = useKeverd();

  if (isLoading) return <div>Loading device profile...</div>;
  if (error) return <div>Failed to identify device. Please refresh.</div>;

  return (
    <div>
      <p>Device ID: {deviceId}</p>
      <p>Risk Score: {riskScore}/100</p>
      <p>Risk Level: {riskScore > 70 ? '⚠️ High' : '✅ Normal'}</p>
    </div>
  );
}

// pages/checkout.jsx (Pages Router)
import { useKeverd } from '@keverdjs/react';

export default function CheckoutPage() {
  const { deviceId, riskScore, isLoading, error } = useKeverd();

  if (isLoading) return <div>Loading device profile...</div>;
  if (error) return <div>Failed to identify device. Please refresh.</div>;

  return (
    <div>
      <p>Device ID: {deviceId}</p>
      <p>Risk Score: {riskScore}/100</p>
      <p>Risk Level: {riskScore > 70 ? '⚠️ High' : '✅ Normal'}</p>
    </div>
  );
}

How It Works

Step	What Happens	Who Triggers It
1. Provider mounts	SDK loads, validates API key	`KeverdProvider`
2. Fingerprinting starts	Device signals collected, API call made	First `useKeverd()` call
3. Data available	`deviceId`, `riskScore` returned to component	Hook re-renders with data

Key point: If no component calls useKeverd(), Keverd stays idle. No API calls are made. No device data is collected.

Complete Example

App Router

// app/components/KeverdWrapper.jsx
'use client';

import { KeverdProvider } from '@keverdjs/react';

export function KeverdWrapper({ children }) {
  return (
    <KeverdProvider apiKey="pk_live_your_api_key_here">
      {children}
    </KeverdProvider>
  );
}

// app/layout.jsx
import { KeverdWrapper } from './components/KeverdWrapper';

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body>
        <KeverdWrapper>
          {children}
        </KeverdWrapper>
      </body>
    </html>
  );
}

// app/checkout/page.jsx
'use client';

import { useKeverd } from '@keverdjs/react';

export default function Checkout() {
  const { deviceId, riskScore, isLoading } = useKeverd();

  if (isLoading) return <div>Verifying device...</div>;

  return (
    <div>
      <h1>Checkout</h1>
      <p>Processing payment from device: {deviceId}</p>
      {riskScore > 70 && (
        <p style={{color: 'red'}}>
          ⚠️ High risk detected. Additional verification required.
        </p>
      )}
    </div>
  );
}

Pages Router

// pages/_app.jsx
import { KeverdProvider } from '@keverdjs/react';

export default function MyApp({ Component, pageProps }) {
  return (
    <KeverdProvider apiKey="pk_live_your_api_key_here">
      <Component {...pageProps} />
    </KeverdProvider>
  );
}

// pages/checkout.jsx
import { useKeverd } from '@keverdjs/react';

export default function Checkout() {
  const { deviceId, riskScore, isLoading } = useKeverd();

  if (isLoading) return <div>Verifying device...</div>;

  return (
    <div>
      <h1>Checkout</h1>
      <p>Processing payment from device: {deviceId}</p>
      {riskScore > 70 && (
        <p style={{color: 'red'}}>
          ⚠️ High risk detected. Additional verification required.
        </p>
      )}
    </div>
  );
}

What About My Backend?

Once useKeverd() has resolved, Keverd automatically injects headers into your HTTP requests:

// Every fetch/axios request gets these headers:
headers: {
  'X-Keverd-Device-ID': 'dev_2x7f9k3m4n5p8q2r',
  'X-Keverd-Risk-Score': '23',
  'X-Keverd-Session-ID': 'sess_abc123'
}

Backend reads the headers. No backend code changes needed beyond reading them.

Using in API Routes

// app/api/payment/route.js (App Router)
export async function POST(request) {
  const headers = request.headers;
  
  const deviceId = headers.get('X-Keverd-Device-ID');
  const riskScore = headers.get('X-Keverd-Risk-Score');
  
  if (riskScore > 70) {
    return Response.json({ error: 'High risk transaction blocked' }, { status: 403 });
  }
  
  // Process payment...
}

// pages/api/payment.js (Pages Router)
export default function handler(req, res) {
  const deviceId = req.headers['x-keverd-device-id'];
  const riskScore = req.headers['x-keverd-risk-score'];
  
  if (riskScore > 70) {
    return res.status(403).json({ error: 'High risk transaction blocked' });
  }
  
  // Process payment...
}

Testing It Works

1. Verify the Hook Triggers the Call

Open DevTools Network tab, then mount a client component with useKeverd(). You should see a request to Keverd’s API.

2. Check the Console

// After useKeverd() resolves:
console.log(window.__KEVERD_DEVICE_ID__);
// Should show: "dev_2x7f9k3m4n5p8q2r"

3. Test Incognito Persistence

// In normal window
await keverd.getDeviceId(); // "dev_2x7f9k3m4n5p8q2r"

// Open incognito, run same code
await keverd.getDeviceId(); // "dev_2x7f9k3m4n5p8q2r" (SAME ID)

4. View Your Dashboard

Visit dashboard.keverd.com to see devices, risk scores, and blocked attempts.

Common Questions

Q: Can I trigger fingerprinting without rendering UI? Yes. Create an invisible client component that calls useKeverd() on mount, or call the imperative API directly (see JavaScript Quickstart). Q: What if I call useKeverd() in multiple components? The SDK deduplicates — only one API call is made, and all components share the result. Q: Does KeverdProvider itself make any API calls? No. It only sets up context. The first useKeverd() call triggers all fingerprinting logic. Q: Can I use useKeverd() in a Server Component? No. Device fingerprinting requires browser APIs (canvas, WebGL, etc.) that only exist on the client. Always use 'use client' in App Router. Q: Will this affect my Core Web Vitals? The SDK is loaded asynchronously and fingerprinting is deferred until useKeverd() is called. It does not block the initial page render.

Key additions for Next.js:
**App Router vs Pages Router** — separate code examples for both
**`'use client'` directive** — explicitly marked on all `useKeverd()` examples since it only works client-side
**API Routes section** — showing how to read Keverd headers in both `app/api/` and `pages/api/` patterns
**Server Component warning** — clear note that `useKeverd()` cannot run in Server Components
**Core Web Vitals note** — addresses a common Next.js concern about bundle size and render blocking

Getting started

SDKS

Overview

Prerequisites

Step 1: Get Your API Key

Step 2: Install the SDK

Step 3: Wrap Your App with KeverdProvider

App Router

Pages Router

Step 4: Initialize Fingerprinting

Basic usage — trigger on component mount:

How It Works

Complete Example

App Router

Pages Router

What About My Backend?

Using in API Routes

Testing It Works

1. Verify the Hook Triggers the Call

2. Check the Console

3. Test Incognito Persistence

4. View Your Dashboard

Common Questions

​Overview

​Prerequisites

​Step 1: Get Your API Key

​Step 2: Install the SDK

​Step 3: Wrap Your App with KeverdProvider

​App Router

​Pages Router

​Step 4: Initialize Fingerprinting

​Basic usage — trigger on component mount:

​How It Works

​Complete Example

​App Router

​Pages Router

​What About My Backend?

​Using in API Routes

​Testing It Works

​1. Verify the Hook Triggers the Call

​2. Check the Console

​3. Test Incognito Persistence

​4. View Your Dashboard

​Common Questions

Overview

Prerequisites

Step 1: Get Your API Key

Step 2: Install the SDK

Step 3: Wrap Your App with KeverdProvider

App Router

Pages Router

Step 4: Initialize Fingerprinting

Basic usage — trigger on component mount:

How It Works

Complete Example

App Router

Pages Router

What About My Backend?

Using in API Routes

Testing It Works

1. Verify the Hook Triggers the Call

2. Check the Console

3. Test Incognito Persistence

4. View Your Dashboard

Common Questions