Get recaptcha api key

<input type="text" name="name" placeholder="Your Name">


<input type="email" name="email" placeholder="Your Email">


<textarea name="message" placeholder="Your Message"></textarea>

 <!-- reCAPTCHA widget -->


<div class="g-recaptcha" data-sitekey="YOUR_SITE_KEY"></div>

 <button type="submit">Send Message</button>

<!-- Hidden input to store the reCAPTCHA token -->


<input type="hidden" id="recaptchaResponse" name="recaptcha_response">

 <button type="submit">Submit</button>

• grecaptcha.ready: Ensures that the reCAPTCHA API is fully loaded before attempting to execute it.
• grecaptcha.execute'YOUR_SITE_KEY', {action: 'your_action_name'}: This function asynchronously generates a token. The action parameter helps Google’s risk analysis. Choose descriptive action names like login, signup, submit_comment, etc.
• token: The then callback receives the reCAPTCHA token. This token is crucial and must be sent to your server for verification using the Secret Key.
• recaptcha_response: A common name for the hidden input field that carries the token to the server.

Remember, both v2 and v3 implementations require a server-side verification step, which we’ll discuss next.

Without it, the front-end implementation alone offers no real protection. Recaptcha cookie

Server-Side Verification: Using Your Secret Key

Implementing the front-end part of reCAPTCHA is only half the battle. The true power of reCAPTCHA lies in its server-side verification. This is where your Secret Key comes into play. After a user interacts with reCAPTCHA or it runs invisibly in the background, Google generates a response token. This token needs to be sent from your front-end to your back-end server, which then sends it to Google’s reCAPTCHA verification API along with your Secret Key. Google processes this request and returns a JSON response indicating whether the interaction was likely human or bot.

The Verification Process

Here’s a breakdown of the server-side verification flow:

1. User Action: A user performs an action on your website e.g., submits a form, clicks a button.
2. Front-End Token Generation: The reCAPTCHA JavaScript on your front-end generates a g-recaptcha-response token for v2 or a token from grecaptcha.execute for v3.
3. Token Transmission: This token is sent to your server along with other form data e.g., in a POST request.
4. Server-Side Request to Google: Your server-side code makes an HTTP POST request to Google’s reCAPTCHA verification API endpoint: https://www.google.com/recaptcha/api/siteverify.
5. Request Parameters: This request must include two critical parameters:
   • secret: Your reCAPTCHA Secret Key.
   • response: The token received from the user’s front-end.
   • Optional remoteip: The user’s IP address. This helps Google’s risk analysis.
6. Google’s Response: Google’s API returns a JSON response.
7. Server-Side Decision: Your server-side code parses Google’s response and makes a decision based on the success field for v2 or the score and action fields for v3.

Example Server-Side Verification PHP

Let’s illustrate with a PHP example. This is a common scenario for web forms.

<?php

// Check if the form was submitted
if $_SERVER === 'POST' {



   // Your Secret Key from the reCAPTCHA Admin Console
    $secretKey = 'YOUR_SECRET_KEY'.



   // Get the reCAPTCHA response token from the POST data


   $recaptchaResponse = $_POST ?? ''. // For v2


   // Or for v3: $recaptchaResponse = $_POST ?? ''.



   // If no reCAPTCHA token is present, something is wrong
    if empty$recaptchaResponse {
        die'reCAPTCHA token missing. Possible bot.'.

    // Prepare data for Google's API request
    $data = 
        'secret'   => $secretKey,
        'response' => $recaptchaResponse,


       'remoteip' => $_SERVER // Optional: user's IP address
    .

    // Initialize cURL for making the HTTP request
    $ch = curl_init.


   curl_setopt$ch, CURLOPT_URL, 'https://www.google.com/recaptcha/api/siteverify'.
    curl_setopt$ch, CURLOPT_POST, true.


   curl_setopt$ch, CURLOPT_POSTFIELDS, http_build_query$data.


   curl_setopt$ch, CURLOPT_RETURNTRANSFER, true. // Return response as a string


   curl_setopt$ch, CURLOPT_SSL_VERIFYPEER, true. // Important for security

    // Execute the request and get the response
    $response = curl_exec$ch.
    $curlError = curl_error$ch.
    curl_close$ch.

    if $curlError {


       die'Error communicating with reCAPTCHA API: ' . $curlError.

    // Decode the JSON response from Google
    $responseData = json_decode$response, true.



   // --- Decision Logic based on reCAPTCHA type ---



   // For reCAPTCHA v2 Checkbox or Invisible Badge
    if $responseData {


       echo 'reCAPTCHA verification successful! Form submitted.'.


       // Proceed with processing your form data e.g., save to database, send email
    } else {
        echo 'reCAPTCHA verification failed. Reasons: '.


       // Log or display error codes for debugging


       foreach $responseData as $errorCode {
            echo $errorCode . ' '.
        }
        echo 'Possible bot.'.


       // Stop processing or provide an error message to the user

    // For reCAPTCHA v3 Score-based


   // if $responseData && $responseData >= 0.7 { // Example threshold


   //     echo 'reCAPTCHA v3 verification successful! Score: ' . $responseData . '. Form submitted.'.


   //     // Optionally check the action name if you set one in the front-end


   //     // if $responseData === 'submit_form' {
    //     //     // ... proceed
    //     // }


   //     // Proceed with processing your form data
    // } else {


   //     echo 'reCAPTCHA v3 verification failed or low score.

Score: ' . $responseData ?? 'N/A' . '. Possible bot.'.
    //     // Depending on the score, you might:


   //     // - Block the request completely score < 0.3


   //     // - Prompt for additional verification 0.3 <= score < 0.7


   //     // - Log the suspicious activity for later review


   //     // - Implement honeypots as a secondary measure
    // }

} else {
    echo 'Access this page via POST request.'.
}

?>

# Key Considerations for Server-Side Verification

*   Security of Secret Key: Never hardcode your Secret Key directly into your publicly accessible source code. Use environment variables, a configuration management system, or a secure secrets management service.
*   Error Handling: Always include robust error handling for network issues cURL errors in the PHP example or unexpected responses from Google's API.
*   IP Address Optional but Recommended: Sending the user's `remoteip` helps Google perform more accurate risk analysis. In PHP, `$_SERVER` typically provides the client's IP.
*   Action Parameter v3: For reCAPTCHA v3, verify the `action` parameter in Google's response. This helps ensure that the token is being used for the intended action e.g., a login token isn't being reused for a comment submission.
*   Threshold Management v3: For v3, the score-based system requires careful calibration. A score of 0.7 might be suitable for a contact form, but for highly sensitive actions like password changes, you might require a higher score e.g., 0.9. Consider what actions to take based on the score:
   *   High Score e.g., >= 0.7: Proceed with the action.
   *   Medium Score e.g., 0.3 - 0.69: Implement secondary verification e.g., email verification, SMS OTP, simple math captcha if absolutely necessary, but prioritize user experience.
   *   Low Score e.g., < 0.3: Block the action and potentially log the attempt.
*   Timeouts: Implement timeouts for your HTTP requests to Google's API to prevent your server from hanging if Google's service is slow or unresponsive.
*   Data Integrity: Ensure that the reCAPTCHA response token is submitted with every relevant form or action. If it's missing, it's a strong indicator of a bot.



By meticulously implementing the server-side verification, you leverage reCAPTCHA's full potential to protect your website from automated threats.

 Monitoring and Analytics in the reCAPTCHA Admin Console



Obtaining and implementing your reCAPTCHA API keys is a significant first step, but the journey doesn't end there.

Google's reCAPTCHA Admin Console offers powerful tools for monitoring the performance of your reCAPTCHA implementation and analyzing bot activity.

This data is invaluable for understanding the types of threats your site faces and for fine-tuning your reCAPTCHA settings.

# Accessing Your Site's Dashboard



After logging into the reCAPTCHA Admin Console, you'll see a list of all the sites you've registered.

Clicking on a specific site label will take you to its dedicated dashboard, which provides a comprehensive overview of its reCAPTCHA performance.

# Key Metrics and Graphs



The dashboard typically displays several key metrics and interactive graphs:

*   Total Requests: The sheer volume of reCAPTCHA requests your site has received over a selected time period e.g., 7 days, 30 days, or custom range. This helps you gauge usage and potential traffic patterns.
*   Security Preference Score reCAPTCHA v3: This is perhaps the most critical metric for v3 implementations. It shows the average score of interactions on your site. A higher average score indicates more human traffic and less bot activity. If this score dips, it might suggest an increase in sophisticated bot attacks that are managing to get higher scores, or that your legitimate users are being flagged more often.
*   Traffic Overview: A graph showing the distribution of human vs. bot traffic over time. This helps you visualize trends in malicious activity. You might see spikes correlating with specific events or bot campaigns.
*   Top 10 Domains: A list of the top domains from which reCAPTCHA requests are originating. This is useful for identifying unexpected sources of traffic or potential misuse of your keys. If you see domains you don't recognize, it might indicate that your Site Key has been compromised or copied to another site.
*   Top 10 Actions reCAPTCHA v3: For v3, this shows the breakdown of reCAPTCHA requests by the `action` name you defined e.g., `login`, `signup`, `submit_form`. This helps you understand which parts of your site are experiencing the most bot activity and adjust your thresholds accordingly. For instance, if your `login` action has a lower average score than your `contact_form` action, you might consider a stricter threshold for login attempts.
*   Threat Breakdown: Google attempts to categorize the types of threats detected, such as automation, suspicious traffic, or potential credential stuffing. While this is a high-level overview, it can provide insights into the nature of attacks.

# Utilizing Analytics for Optimization



The data presented in the Admin Console is not just for curiosity. it's actionable intelligence:

*   Adjusting v3 Thresholds: If you notice a high volume of requests with medium scores e.g., 0.3-0.7 for a particular action, you might need to lower your server-side threshold slightly to let more legitimate users through, or conversely, raise it if too many bots are passing. This is an iterative process.
*   Identifying Attack Vectors: A sudden surge in requests from a specific region or IP range, or targeting a particular action, can signal an ongoing attack. This allows you to implement additional safeguards or adjust your firewall rules.
*   Detecting Key Misuse: If you see a large number of requests from domains not explicitly listed in your "Domains" section, it's a strong indicator that your Site Key might be copied and used elsewhere. In such cases, you should consider resetting your keys.
*   Performance Monitoring: If the "Total Requests" significantly drops without a corresponding decrease in your website traffic, it could indicate an issue with your reCAPTCHA implementation e.g., the script isn't loading, or the site key is incorrect.
*   Resource Allocation: Understanding which areas of your site are most targeted by bots can help you allocate security resources more effectively. For example, if your registration page is constantly under attack, you might invest in more robust anti-fraud measures there.

# Alerts and Notifications



As mentioned earlier, enabling "Send alerts to owners" is crucial. Google will notify you via email if:

*   Significant Decrease in Traffic: Your reCAPTCHA usage drops substantially, potentially indicating an implementation issue.
*   Spike in Suspicious Traffic: There's an unusual increase in activity flagged as potentially malicious.
*   Low Security Preference Score: For v3, if your average score consistently drops below a certain threshold, indicating a rise in successful bot activity.



Regularly checking your reCAPTCHA Admin Console dashboard and responding to alerts will help you maintain an effective defense against automated threats and ensure a smooth experience for your human users.

 Troubleshooting Common reCAPTCHA Issues



Even with careful implementation, you might encounter issues with reCAPTCHA.

Here's a breakdown of common problems and their solutions, along with some proactive advice.

# 1. "ERROR for site owner: Invalid domain for site key"

This is one of the most common errors.

*   Cause: The domain where your reCAPTCHA is implemented e.g., `yourwebsite.com` is not listed in the "Domains" section of your reCAPTCHA API key settings in the Admin Console. This also happens if you're developing locally and haven't added `localhost` or `127.0.0.1`.
*   Solution:


   1.  Go to the reCAPTCHA Admin Console https://www.google.com/recaptcha/admin.
    2.  Select the site key in question.


   3.  Under "Domains," add the exact domain e.g., `example.com`, `www.example.com`, `localhost` where you're trying to use reCAPTCHA. Remember to save changes.

# 2. reCAPTCHA Widget Not Appearing or Not Loading

*   Cause A: Incorrect Site Key: The `data-sitekey` in your HTML for v2 or the `render` parameter in the script tag for v3 is misspelled or incorrect.
*   Solution A: Double-check your Site Key against the one in the Admin Console. Copy and paste to avoid typos.
*   Cause B: JavaScript Errors: Other JavaScript errors on your page might be preventing the reCAPTCHA script from loading or executing correctly.
*   Solution B: Open your browser's developer console F12, then check the "Console" tab and look for JavaScript errors. Fix any unrelated errors first.
*   Cause C: Script Not Loaded: The reCAPTCHA JavaScript API `https://www.google.com/recaptcha/api.js` is not included in your HTML or is being blocked.
*   Solution C: Ensure the script tag is present and correctly placed preferably before `</body>` or in `<head>`. Check if any ad blockers or browser extensions are blocking the script.
*   Cause D: Content Security Policy CSP: Your website's CSP might be preventing scripts or resources from `www.google.com` or `www.gstatic.com` from loading.
*   Solution D: Adjust your CSP to allow `script-src` and `frame-src` from `www.google.com` and `www.gstatic.com`.


   Content-Security-Policy: script-src 'self' www.google.com www.gstatic.com. frame-src www.google.com.

# 3. Server-Side Verification Fails or Returns `false`



This means your server isn't getting a successful `success: true` or a high enough `score` from Google.

*   Cause A: Incorrect Secret Key: Your server-side code is using the wrong Secret Key or it's misspelled.
*   Solution A: Double-check your Secret Key. Copy and paste it securely into your server's environment variables or configuration file.
*   Cause B: Missing reCAPTCHA Response Token: The `g-recaptcha-response` v2 or `recaptcha_response` v3 token is not being sent from the front-end to the back-end, or your back-end isn't correctly parsing it.
*   Solution B: Verify that the `name` attribute of your hidden input field or the parameter name in your AJAX request matches what your server-side code expects. Use your browser's network tab F12 -> "Network" to inspect the form submission or AJAX request and confirm the token is being sent.
*   Cause C: Network Issues: Your server cannot reach `https://www.google.com/recaptcha/api/siteverify` due to firewall restrictions, DNS issues, or temporary Google service outages.
*   Solution C: Check your server's network connectivity. Ensure your firewall allows outbound HTTPS connections to Google. Implement robust error handling and logging for API requests.
*   Cause D: Mismatched IP Address Rare: If you're sending the `remoteip` parameter to Google, ensure it's the actual user's IP, not your server's IP or a proxy's IP. Incorrect `remoteip` can sometimes lead to lower scores or failed verifications.
*   Solution D: Verify how `remoteip` is determined on your server. Be aware of `X-Forwarded-For` headers if you're behind a proxy or load balancer.
*   Cause E: Low Score v3 Specific: For reCAPTCHA v3, the score might be too low, meaning Google thinks the user is likely a bot, even if they are human.
*   Solution E:
   1.  Check Admin Console: Go to your reCAPTCHA Admin Console and check the "Security Preference Score" for the specific action.
   2.  Adjust Threshold: Consider lowering your server-side threshold slightly if too many legitimate users are being blocked. For instance, if you're blocking anything below 0.7, try 0.6.
   3.  Honeypots/Secondary Verification: For low scores, instead of outright blocking, consider secondary verification like a simple, accessible honeypot field hidden from humans, but bots often fill it.

# 4. reCAPTCHA V2 Audio Challenge Not Working

*   Cause: Often related to Content Security Policy CSP blocking audio sources, or specific browser extensions interfering.
*   Solution: Check your CSP to ensure `media-src` allows `www.google.com` and `www.gstatic.com`. Temporarily disable browser extensions to see if they are the cause.

# General Troubleshooting Tips

*   Check Browser Console: Always start by checking your browser's developer console F12 for JavaScript errors, network request failures, or reCAPTCHA-specific error messages.
*   Check Server Logs: Examine your server-side application logs for errors related to reCAPTCHA API calls, unhandled exceptions, or issues parsing Google's response.
*   Use the Admin Console: The reCAPTCHA Admin Console is your best friend. It shows you if requests are even reaching Google, what scores are being returned for v3, and potential error codes.
*   Read Google's Documentation: Google's official reCAPTCHA documentation is comprehensive and constantly updated. Refer to it for specific error codes and detailed implementation guides.



By systematically approaching these troubleshooting steps, you can quickly identify and resolve most reCAPTCHA implementation issues, ensuring your website remains protected.

 Advanced reCAPTCHA Strategies and Best Practices



Beyond basic implementation, there are advanced strategies and best practices that can significantly enhance reCAPTCHA's effectiveness, improve user experience, and provide more granular control over bot mitigation.

# 1. Utilizing reCAPTCHA v3 Action Parameter



For reCAPTCHA v3, the `action` parameter `grecaptcha.execute'YOUR_SITE_KEY', {action: 'your_action_name'}` is not just a label.

it's a powerful tool for Google's risk analysis and your own analytics.

*   Purpose: It tells Google what specific action the user is performing e.g., `login`, `signup`, `submit_comment`, `checkout`. This helps Google's machine learning model tailor its risk assessment for that specific context.
*   Benefits:
   *   Improved Accuracy: Google can apply more relevant fraud detection models for specific actions, leading to better human/bot distinction.
   *   Better Analytics: In the reCAPTCHA Admin Console, you can view performance metrics scores, traffic broken down by action. This allows you to identify which parts of your site are most targeted by bots.
   *   Granular Thresholds: You can set different score thresholds for different actions on your server-side. For example, require a higher score e.g., 0.9 for a password reset, but allow a lower score e.g., 0.5 for a contact form submission.

# 2. Implementing Adaptive Security with reCAPTCHA v3 Scores



Instead of a simple pass/fail, reCAPTCHA v3's score allows for a more nuanced, adaptive security approach.

*   Tiered Responses:
   *   High Score e.g., 0.7 - 1.0: Allow the action immediately. This is your trusted user group.
   *   Medium Score e.g., 0.3 - 0.69: Implement secondary verification. This could be:
       *   A simple, accessible honeypot field.
       *   An email verification step.
       *   A multi-factor authentication MFA prompt if applicable.
       *   A rate-limiting mechanism for the user's IP.
       *   In rare, unavoidable cases, a reCAPTCHA v2 checkbox challenge though this negates the v3 seamless experience.
   *   Low Score e.g., 0.0 - 0.29: Block the action outright. Log the attempt for security monitoring.
   *   Reduced Friction: High-confidence human users experience no interruption.
   *   Enhanced Security: Suspicious requests are subjected to more rigorous checks.

# 3. Using Honeypots as a Secondary Defense



Honeypots are hidden form fields designed to catch bots.

Humans won't see them, but bots often fill out every field they encounter.

*   Implementation: Add a hidden input field to your form using CSS e.g., `display: none.` or `position: absolute. left: -9999px.`.
*   Example HTML:
    <div style="display:none.">


       <input type="text" name="honeypot_field" value="">
    </div>
*   Server-Side Check: On your server, if `honeypot_field` contains any value, you know it's a bot, and you can immediately reject the submission.
   *   Simple & Effective: Very easy to implement and highly effective against unsophisticated bots.
   *   Complements reCAPTCHA: Adds another layer of defense, especially useful in conjunction with v3's scoring.
   *   Zero User Impact: Completely invisible and frictionless for legitimate users.

# 4. Rate Limiting for IP Addresses and User Accounts



Regardless of reCAPTCHA, implementing rate limiting is a fundamental security practice.

*   IP-Based Rate Limiting: Limit the number of requests e.g., form submissions, login attempts from a single IP address within a specific time frame.
*   Account-Based Rate Limiting: Limit the number of login attempts for a specific user account to prevent brute-force attacks.
   *   Deters Brute-Force Attacks: Prevents bots from rapidly guessing passwords or spamming forms.
   *   Protects Resources: Reduces the load on your server from excessive requests.
   *   Works Hand-in-Hand: Even if a bot manages to get a good reCAPTCHA score, rate limiting can still stop it from overwhelming your system.

# 5. Regular Monitoring and Key Management

*   Monitor Admin Console: Regularly check your reCAPTCHA Admin Console for traffic trends, score fluctuations, and alerts. This allows you to react quickly to new bot attack patterns or implementation issues.
*   Key Rotation: While not strictly required by Google, consider periodically regenerating your reCAPTCHA keys e.g., annually or if you suspect a compromise. This adds another layer of security.
*   Secure Key Storage: Always store your Secret Key securely, away from your public codebase. Use environment variables or a secrets management system.



By integrating these advanced strategies and adhering to best practices, you can build a more resilient and user-friendly defense against automated threats on your website, ensuring a more secure digital environment for your users.

 Ethical Considerations and User Experience with reCAPTCHA



While reCAPTCHA is an indispensable tool for web security, it's crucial to approach its implementation with ethical considerations and user experience in mind.

The goal is to deter bots without inadvertently penalizing or frustrating legitimate human users.

# User Privacy and Data Collection



reCAPTCHA, being a Google service, collects data about user interactions on your site. This includes:

*   IP address: To identify the user's location and track potential bot networks.
*   Browser and device data: User agent, screen resolution, browser plugins, operating system, etc.
*   Cookies: Google reCAPTCHA sets its own cookies to track user behavior across sites.
*   Mouse movements and key presses: Especially with v3, this data is used to analyze human-like behavior.
*   Pages visited: Google may analyze the pages a user navigates to before interacting with reCAPTCHA.

*   Ethical Obligation: As a website owner, you have an ethical and often legal obligation e.g., GDPR, CCPA to inform your users about the use of reCAPTCHA and its data collection practices.
*   Privacy Policy: Your website's privacy policy should explicitly mention the use of Google reCAPTCHA, link to Google's Privacy Policy and Terms of Service, and explain what data is collected and for what purpose. A simple statement like, "This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply," is a good starting point and is often automatically included by reCAPTCHA in v3 implementations.

# Accessibility Challenges



reCAPTCHA v2's visual challenges can pose significant accessibility barriers for users with disabilities:

*   Visually Impaired Users: Image challenges are difficult or impossible without visual assistance. While reCAPTCHA offers an audio challenge, it can sometimes be unclear or difficult to understand, especially for users with hearing impairments or those in noisy environments.
*   Motor Impairment: Clicking specific areas in an image or performing precise mouse movements can be challenging.
*   Cognitive Impairment: Complex or abstract image recognition tasks might be confusing.

*   Best Practice:
   *   Prioritize reCAPTCHA v3: For new implementations, reCAPTCHA v3 is generally superior for accessibility as it requires no explicit user interaction.
   *   Test with Assistive Technologies: If you must use v2, rigorously test your implementation with screen readers and other assistive technologies to ensure a reasonable user experience.
   *   Provide Alternatives if possible: For highly sensitive actions, consider offering alternative verification methods that cater to diverse needs, such as email or SMS-based verification, if appropriate for your application. However, reCAPTCHA is specifically designed to be broadly accessible while combating bots.

# Avoiding User Frustration



The core tension with bot protection is balancing security with user experience.

Overly aggressive reCAPTCHA settings can lead to legitimate users abandoning your site.

*   reCAPTCHA v2 Frustration:
   *   Repeated Challenges: If a user repeatedly fails challenges or is presented with many challenges, they might give up.
   *   Ambiguous Images: Images that are difficult to discern can be very frustrating.
   *   Slow Loading Times: If the reCAPTCHA widget loads slowly, it creates a bottleneck.
*   reCAPTCHA v3 Frustration Less Obvious:
   *   False Positives: If your reCAPTCHA v3 score threshold is too high, legitimate users with "suspicious" browsing patterns e.g., using a VPN, being on a corporate network, having certain browser extensions might be incorrectly flagged as bots and blocked. This is a subtle form of frustration because the user doesn't know *why* they're blocked.

   *   Calibrate v3 Thresholds Carefully: Use your Admin Console analytics to fine-tune your v3 score thresholds. Start with a more lenient approach and gradually tighten it based on observed bot activity and user feedback.
   *   Monitor User Feedback: Pay attention to user complaints about being blocked or having difficulty. This feedback is critical for adjusting your strategy.
   *   Consider Context: A registration form might tolerate a slightly higher friction than a simple contact form. Adjust your reCAPTCHA version and settings based on the sensitivity of the action.
   *   Graceful Degradation/Alternative Actions: For critical actions, if a reCAPTCHA verification fails for a legitimate user, provide a clear error message and potentially an alternative way to complete the action e.g., "If you are having trouble, please contact support at...".



By prioritizing transparency, accessibility, and user-centric design in your reCAPTCHA implementation, you can create a more secure online environment that respects your users and their experience.

 Frequently Asked Questions

# What is reCAPTCHA and why do I need an API key?


reCAPTCHA is a free service from Google that helps protect websites from spam and abuse by distinguishing human users from automated bots.

You need an API key specifically, a Site Key and a Secret Key to integrate this service into your website or application, allowing it to communicate with Google's reCAPTCHA verification servers.

# How do I get a reCAPTCHA Site Key and Secret Key?


To get reCAPTCHA keys, go to the Google reCAPTCHA Admin Console at `https://www.google.com/recaptcha/admin/create`. You'll need to sign in with your Google account, register a new site by providing a label, choosing the reCAPTCHA type v2 or v3, entering your website's domains, accepting the terms, and then submitting the form.

Both the Site Key public and Secret Key private will be provided.

# Is reCAPTCHA free to use?


Yes, reCAPTCHA is a free service provided by Google.

There are no direct costs associated with using it for standard website protection.

# Which reCAPTCHA version should I choose: v2 or v3?


For most modern applications, reCAPTCHA v3 is recommended because it runs invisibly in the background, providing a seamless user experience.

It returns a score indicating the likelihood of an interaction being human.

reCAPTCHA v2 requires explicit user interaction like clicking an "I'm not a robot" checkbox or solving image challenges, which can add friction but provides clear user feedback.

# Can I use the same reCAPTCHA API key for multiple domains?


Yes, you can use the same reCAPTCHA API key for multiple domains.

When registering your site in the reCAPTCHA Admin Console, you can add multiple domains one per line in the "Domains" field.

Subdomains are typically covered if the root domain is listed.

# How do I add `localhost` for local development?


To test reCAPTCHA on your local machine, you must add `localhost` or `127.0.0.1` to the list of domains in your reCAPTCHA API key settings within the Admin Console.

Without it, reCAPTCHA will display an "ERROR for site owner: Invalid domain for site key" message.

# Where do I put the Site Key in my HTML?


The Site Key public key is embedded in your website's client-side code.

For reCAPTCHA v2, you place it in the `data-sitekey` attribute of the `<div class="g-recaptcha">` element.

For reCAPTCHA v3, you typically include it in the `render` parameter of the reCAPTCHA script tag `<script src="https://www.google.com/recaptcha/api.js?render=YOUR_SITE_KEY"></script>`.

# Where do I use the Secret Key?


The Secret Key private key is used on your server-side code to verify the user's reCAPTCHA response with Google's API.

This key must be kept confidential and should never be exposed in your client-side code HTML, JavaScript.

# What is the `g-recaptcha-response` token?


The `g-recaptcha-response` token is the value generated by the reCAPTCHA JavaScript on the client-side after a user completes a reCAPTCHA challenge v2 or after the invisible verification runs v3. This token must be sent to your server for verification against Google's API using your Secret Key.

# What does the reCAPTCHA v3 score mean?


For reCAPTCHA v3, the score is a number between 0.0 and 1.0. A score of 1.0 indicates a very high likelihood that the interaction is human, while 0.0 indicates a very high likelihood that it's a bot.

You define a threshold on your server-side to decide what action to take based on the score.

# Can reCAPTCHA block all bots?


While reCAPTCHA is highly effective, no single security solution can guarantee 100% protection against all sophisticated bots.

It significantly reduces automated abuse but should ideally be part of a layered security strategy that might include rate limiting, honeypots, and other anti-fraud measures.

# Why is my reCAPTCHA not showing up?


Common reasons include: incorrect Site Key, JavaScript errors on your page, the reCAPTCHA script not being loaded, or your domain not being whitelisted in the reCAPTCHA Admin Console.

Check your browser's developer console for errors and verify your Admin Console settings.

# What is an "ERROR for site owner: Invalid key type"?


This error typically occurs if you're trying to use a reCAPTCHA v3 Site Key with a v2 implementation or vice-versa. Ensure that the type of key you generated matches the reCAPTCHA version you are trying to implement on your website.

# How do I reset or regenerate my reCAPTCHA keys?


You can regenerate your reCAPTCHA Site Key and Secret Key from within the reCAPTCHA Admin Console.

Navigate to your site's settings, and you should find an option to "Regenerate Keys." This will invalidate the old keys, so you'll need to update them immediately on your website.

# Does reCAPTCHA affect website performance?


reCAPTCHA loads external JavaScript and makes requests to Google's servers.

While Google optimizes these scripts for performance, it can add a small overhead to your page load time.

Using `async` and `defer` attributes on the script tag helps mitigate this.

reCAPTCHA v3 generally has less perceived impact on user experience than v2.

# Do I need to inform users about reCAPTCHA?


Yes, for transparency and compliance with privacy regulations like GDPR, CCPA, you should inform users that your site uses reCAPTCHA.

Google recommends including a disclaimer and links to their Privacy Policy and Terms of Service in your site's privacy policy.

# Can reCAPTCHA cause false positives block real users?


Yes, especially with reCAPTCHA v3, if your server-side score threshold is set too high, legitimate users with unusual browsing patterns e.g., using a VPN, certain browser extensions, or being on a corporate network with many users sharing an IP might occasionally be flagged as bots.

It's crucial to monitor your Admin Console and adjust thresholds.

# What is the `action` parameter in reCAPTCHA v3?


The `action` parameter in reCAPTCHA v3 `grecaptcha.execute'YOUR_SITE_KEY', {action: 'your_action_name'}` helps Google understand the context of the user's interaction e.g., `login`, `signup`, `submit_comment`. This improves Google's risk analysis and allows you to view detailed analytics and set different thresholds per action in the Admin Console.

# Can I use reCAPTCHA for mobile apps?


Yes, reCAPTCHA offers specific versions for mobile apps.

For Android applications, you can select "reCAPTCHA Android" when registering your site in the Admin Console.

There's also Firebase App Check with reCAPTCHA for iOS and Android.

# What should I do if my Secret Key is compromised?


If your Secret Key is compromised e.g., accidentally exposed in public code, you should immediately regenerate a new pair of keys from the reCAPTCHA Admin Console.

Once regenerated, update your server-side code with the new Secret Key to prevent unauthorized verification requests.