Python (Flask) | CAPTCHACAT

Integration guide for Python applications using Flask.

Full Example

A complete working example is available on GitHub: Captchacat-Integrations/Python-Flask

Django

For Django-specific integration, see the Django guide.

Requirements#

requirements.txt

flask
requests

Configuration#

Set your Captchacat credentials:

app.py

CAPTCHACAT_API_KEY = ""   # Your API key
CAPTCHACAT_SITE_KEY = ""  # Your site key

Validation Function#

Create a function to validate the CAPTCHA token:

app.py

import requests
 
def validate_captcha_token(token: str) -> bool:
    """Validate the CAPTCHA token with the server."""
    if not token:
        return False
 
    try:
        response = requests.post(
            "https://challenge.captchacat.com/validate_token",
            json={
                "api_key": CAPTCHACAT_API_KEY,
                "token": token
            },
            timeout=10
        )
        return response.ok
    except requests.RequestException:
        return False

Template#

Create a form template with the widget:

templates/index.html

<!DOCTYPE html>
<html>
<head>
  <title>Login Form</title>
  <script src="https://challenge.captchacat.com/ray/widget.js"></script>
</head>
<body>
  <form action="/submit" method="POST">
    <input type="text" name="username" placeholder="Username" required />
    <input type="password" name="password" placeholder="Password" required />
 
    <div class="captcha-widget" data-sitekey="{{ site_key }}"></div>
 
    <button type="submit">Sign In</button>
  </form>
</body>
</html>

Flask Routes#

app.py

from flask import Flask, render_template, request
 
app = Flask(__name__)
 
@app.route("/")
def index():
    return render_template("index.html", site_key=CAPTCHACAT_SITE_KEY)
 
@app.route("/submit", methods=["POST"])
def submit():
    token = request.form.get("captchacat-token", "")
 
    if not validate_captcha_token(token):
        return "CAPTCHA verification failed", 400
 
    # Token valid - process the form
    username = request.form.get("username")
    # ... handle form data
 
    return "Login successful!"
 
if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)