vectorCAPTCHA

The highest security captcha solution that humans can actually pass.

vectorCAPTCHA challenges users to draw a simple vector symbol. It analyses the stroke path, speed, jitter, and shape, not just a checkbox click.

No third party tracking. No Cookie Banner required. No reCAPTCHA. Served directly from captcha.linkifier.me

Generate your API keys

Enter your domain to get a free site key and secret key. No account needed.

Site Key , public, safe to embed
Secret Key , private, server-side only

Save your secret key now, it cannot be recovered later. Use it only in your backend when calling /validate. Never expose it in client-side code.

Integration guide

1
Add the widget script to your page
Drop one script tag with your site key. The widget renders automatically before the tag, or into any div[data-sitekey] container you provide.
2
Collect the token on success
When the user passes, a short-lived vc_tok_… token is fired via a DOM event and/or your named callback. Send it to your server with your form data.
3
Validate server-side
POST the token and your secret key to https://captcha.linkifier.me/validate. Tokens are single-use and expire in 5 minutes.
HTML embed
Node.js
PHP
Python

        


        
validate response

        

            
            

                Field
                Type
                Description
            

            
            
            

                valid
                boolean
                Whether the captcha passed and the token was genuine.
            

            

                score
                0 – 100
                Humanness confidence. ≥ 58 = pass. Use for risk-based decisions.
            

            

                error
                string?
                Only on failure. E.g. token_expired,
                    invalid_secret.