Integrating reCAPTCHA v3 in Next.js
Tags: webdev, nextjs, javascript, security
Published: 2024-06-16 17:05:51

#### Step 1: Obtain reCAPTCHA v3 credentials

1. **Access Google reCAPTCHA page:**
   - Visit [Google reCAPTCHA admin console](https://www.google.com/recaptcha/admin/).
   - Log in with your Google account if necessary.

2. **Register your website:**
   - Click on "V3" at the top to register a new key for reCAPTCHA v3.
   - Fill out the form with your project name and domains where reCAPTCHA will be used.

3. **Get site keys:**
   - After registering your site, Google will provide two keys: the site key and the secret key. These keys are essential for integrating reCAPTCHA v3 into your web application.

#### Step 2: Setup in your Next.js application

1. **Install necessary npm package:**
   ```bash
   npm install @react-google-recaptcha-v3
   ```

2. **Create a reCAPTCHA component:**
   - Create a React component in your Next.js project to handle reCAPTCHA v3 logic.
   ```jsx
   // components/Recaptcha.js
   import { useEffect } from 'react';
   import { useGoogleReCaptcha } from 'react-google-recaptcha-v3';

   const Recaptcha = ({ onVerify }) => {
     const { executeRecaptcha } = useGoogleReCaptcha();

     useEffect(() => {
       const verifyCallback = async () => {
         if (executeRecaptcha) {
           const token = await executeRecaptcha();
           onVerify(token); // Send token to backend or handle verification here
         }
       };
       verifyCallback();
     }, [executeRecaptcha, onVerify]);

     return null; // This component doesn't render anything visible in the DOM
   };

   export default Recaptcha;
   ```

3. **Integrate the component into your form:**
   ```jsx
   // contact.js
   import Recaptcha from '../components/Recaptcha';

   const ContactPage = () => {
     const handleRecaptchaVerify = (token) => {
       console.log('reCAPTCHA Token:', token);
       // Send token to server for verification
     };

     return (
       <div>
         {/* Your form goes here */}
         <form>
           {/* Other form fields */}
           <Recaptcha onVerify={handleRecaptchaVerify} />
           <button type="submit">Submit</button>
         </form>
       </div>
     );
   };

   export default ContactPage;
   ```

4. **Server-side setup:**
   - In your backend (Node.js, Python, PHP, etc.), verify the reCAPTCHA v3 token using the provided secret key from Google.

### Differences between reCAPTCHA v2 and reCAPTCHA v3

1. **Interaction mode:**
   - **reCAPTCHA v2:** Requires users to solve a visible challenge like selecting images or entering text.
   - **reCAPTCHA v3:** Operates in the background and evaluates user behavior to provide a risk score.

2. **Visibility for users:**
   - **reCAPTCHA v2:** Is visible to users as it presents an explicit challenge.
   - **reCAPTCHA v3:** Is invisible to users, working behind the scenes without requiring explicit user interaction.

3. **Use of scores:**
   - **reCAPTCHA v2:** Does not generate a score; it only validates correct challenge responses.
   - **reCAPTCHA v3:** Provides a score from 0.0 to 1.0 indicating the likelihood that the user is a bot.

4. **Implementation:**
   - **reCAPTCHA v2:** Requires including a widget in the form and backend verification.
   - **reCAPTCHA v3:** Integrates via a frontend API, with primary verification done on the backend using the secret key.

### Additional considerations

- **Handling `null` in `executeRecaptcha`:** You may encounter cases where `executeRecaptcha` could be `null` temporarily, especially during component initialization. Here's how to handle it:

  ```jsx
  // Inside useEffect in Recaptcha.js
  useEffect(() => {
    const verifyCallback = async () => {
      if (executeRecaptcha) {
        const token = await executeRecaptcha();
        onVerify(token); // Send token to backend or handle verification here
      }
    };
    if (executeRecaptcha !== null) {
      verifyCallback();
    }
  }, [executeRecaptcha, onVerify]);
  ```

- **Additional References:** For more technical details or troubleshooting specific issues, you can refer to the [official Google documentation for reCAPTCHA v3](https://developers.google.com/recaptcha/docs/v3) or explore additional resources within the developer community.

This guide provides a solid foundation for effectively integrating reCAPTCHA v3 into your Next.js application, enhancing both security and user experience simultaneously.