Validate the token

const SECRET_KEY = "your-secret-key";

async function validateTurnstile(token, remoteip) {
	try {
		const response = await fetch(
			"https://challenges.cloudflare.com/turnstile/v0/siteverify",
			{
				method: "POST",
				headers: {
					"Content-Type": "application/json",
				},
				body: JSON.stringify({
					secret: SECRET_KEY,
					response: token,
					remoteip: remoteip,
				}),
			},
		);

		const result = await response.json();
		return result;
	} catch (error) {
		console.error("Turnstile validation error:", error);
		return { success: false, "error-codes": ["internal-error"] };
	}
}

const SECRET_KEY = "your-secret-key";

async function validateTurnstile(token, remoteip) {
	const formData = new FormData();
	formData.append("secret", SECRET_KEY);
	formData.append("response", token);
	formData.append("remoteip", remoteip);

	try {
		const response = await fetch(
			"https://challenges.cloudflare.com/turnstile/v0/siteverify",
			{
				method: "POST",
				body: formData,
			},
		);

		const result = await response.json();
		return result;
	} catch (error) {
		console.error("Turnstile validation error:", error);
		return { success: false, "error-codes": ["internal-error"] };
	}
}

// Usage in form handler
async function handleFormSubmission(request) {
	const body = await request.formData();
	const token = body.get("cf-turnstile-response");
	const ip =
		request.headers.get("CF-Connecting-IP") ||
		request.headers.get("X-Forwarded-For") ||
		"unknown";

	const validation = await validateTurnstile(token, ip);

	if (validation.success) {
		// Token is valid - process the form
		console.log("Valid submission from:", validation.hostname);
		return processForm(body);
	} else {
		// Token is invalid - reject the submission
		console.log("Invalid token:", validation["error-codes"]);
		return new Response("Invalid verification", { status: 400 });
	}
}

<?php
function validateTurnstile($token, $secret, $remoteip = null) {
    $url = 'https://challenges.cloudflare.com/turnstile/v0/siteverify';

    $data = [
        'secret' => $secret,
        'response' => $token
    ];

    if ($remoteip) {
        $data['remoteip'] = $remoteip;
    }

    $options = [
        'http' => [
            'header' => "Content-type: application/x-www-form-urlencoded\r\n",
            'method' => 'POST',
            'content' => http_build_query($data)
        ]
    ];

    $context = stream_context_create($options);
    $response = file_get_contents($url, false, $context);

    if ($response === FALSE) {
        return ['success' => false, 'error-codes' => ['internal-error']];
    }

    return json_decode($response, true);

}

// Usage
$secret_key = 'your-secret-key';
$token = $_POST['cf-turnstile-response'] ?? '';
$remoteip = $\_SERVER['HTTP_CF_CONNECTING_IP'] ??
$\_SERVER['HTTP_X_FORWARDED_FOR'] ??
$\_SERVER['REMOTE_ADDR'];

$validation = validateTurnstile($token, $secret_key, $remoteip);

if ($validation['success']) {
// Valid token - process form
echo "Form submission successful!";
// Process your form data here
} else {
// Invalid token - show error
echo "Verification failed. Please try again.";
error_log('Turnstile validation failed: ' . implode(', ', $validation['error-codes']));
}
?>

import requests

def validate_turnstile(token, secret, remoteip=None):
    url = 'https://challenges.cloudflare.com/turnstile/v0/siteverify'

    data = {
        'secret': secret,
        'response': token
    }

    if remoteip:
        data['remoteip'] = remoteip

    try:
        response = requests.post(url, data=data, timeout=10)
        response.raise_for_status()
        return response.json()
    except requests.RequestException as e:
        print(f"Turnstile validation error: {e}")
        return {'success': False, 'error-codes': ['internal-error']}

# Usage with Flask
from flask import Flask, request, jsonify

app = Flask(__name__)
SECRET_KEY = 'your-secret-key'

@app.route('/submit-form', methods=['POST'])
def submit_form():
    token = request.form.get('cf-turnstile-response')
    remoteip = request.headers.get('CF-Connecting-IP') or \
               request.headers.get('X-Forwarded-For') or \
               request.remote_addr

    validation = validate_turnstile(token, SECRET_KEY, remoteip)

    if validation['success']:
        # Valid token - process form
        return jsonify({'status': 'success', 'message': 'Form submitted successfully'})
    else:
        # Invalid token - reject submission
        return jsonify({
            'status': 'error',
            'message': 'Verification failed',
            'errors': validation['error-codes']
        }), 400

import org.springframework.web.client.RestTemplate;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;

@Service
public class TurnstileService {
private static final String SITEVERIFY_URL = "https://challenges.cloudflare.com/turnstile/v0/siteverify";
private final String secretKey = "your-secret-key";
private final RestTemplate restTemplate = new RestTemplate();

    public TurnstileResponse validateToken(String token, String remoteip) {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

        MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
        params.add("secret", secretKey);
        params.add("response", token);
        if (remoteip != null) {
            params.add("remoteip", remoteip);
        }

        HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<>(params, headers);

        try {
            ResponseEntity<TurnstileResponse> response = restTemplate.postForEntity(
                SITEVERIFY_URL, request, TurnstileResponse.class);
            return response.getBody();
        } catch (Exception e) {
            TurnstileResponse errorResponse = new TurnstileResponse();
            errorResponse.setSuccess(false);
            errorResponse.setErrorCodes(List.of("internal-error"));
            return errorResponse;
        }
    }

}

// Controller usage
@PostMapping("/submit-form")
public ResponseEntity<?> submitForm(
@RequestParam("cf-turnstile-response") String token,
HttpServletRequest request) {

    String remoteip = request.getHeader("CF-Connecting-IP");
    if (remoteip == null) {
        remoteip = request.getHeader("X-Forwarded-For");
    }
    if (remoteip == null) {
        remoteip = request.getRemoteAddr();
    }

    TurnstileResponse validation = turnstileService.validateToken(token, remoteip);

    if (validation.isSuccess()) {
        // Valid token - process form
        return ResponseEntity.ok("Form submitted successfully");
    } else {
        // Invalid token - reject submission
        return ResponseEntity.badRequest()
            .body("Verification failed: " + validation.getErrorCodes());
    }

}

using System.Text.Json;

public class TurnstileService
{
    private readonly HttpClient _httpClient;
    private readonly string _secretKey = "your-secret-key";
    private const string SiteverifyUrl = "https://challenges.cloudflare.com/turnstile/v0/siteverify";

    public TurnstileService(HttpClient httpClient)
    {
        _httpClient = httpClient;
    }

    public async Task<TurnstileResponse> ValidateTokenAsync(string token, string remoteip = null)
    {
        var parameters = new Dictionary<string, string>
        {
            { "secret", _secretKey },
            { "response", token }
        };

        if (!string.IsNullOrEmpty(remoteip))
        {
            parameters.Add("remoteip", remoteip);
        }

        var postContent = new FormUrlEncodedContent(parameters);

        try
        {
            var response = await _httpClient.PostAsync(SiteverifyUrl, postContent);
            var stringContent = await response.Content.ReadAsStringAsync();

            return JsonSerializer.Deserialize<TurnstileResponse>(stringContent);
        }
        catch (Exception ex)
        {
            return new TurnstileResponse
            {
                Success = false,
                ErrorCodes = new[] { "internal-error" }
            };
        }
    }
}

// Controller usage
[HttpPost("submit-form")]
public async Task<IActionResult> SubmitForm([FromForm] string cfTurnstileResponse)
{
    var remoteip = HttpContext.Request.Headers["CF-Connecting-IP"].FirstOrDefault() ??
                   HttpContext.Request.Headers["X-Forwarded-For"].FirstOrDefault() ??
                   HttpContext.Connection.RemoteIpAddress?.ToString();

    var validation = await _turnstileService.ValidateTokenAsync(cfTurnstileResponse, remoteip);

    if (validation.Success)
    {
        // Valid token - process form
        return Ok("Form submitted successfully");
    }
    else
    {
        // Invalid token - reject submission
        return BadRequest($"Verification failed: {string.Join(", ", validation.ErrorCodes)}");
    }
}