WebCaptcha is live: set it up in five minutes

WebCaptcha is our human-or-bot check for login, sign-up, account recovery and other sensitive forms. It is included in every plan and is added to a page with a single tag.

Three modes and one challenge

The mode is chosen per site key in your workspace:

• Automatic — the widget assesses the session itself and decides whether to show a check. Most visitors pass without any extra steps.
• Checkbox — the classic one-click “I’m not a robot”, for when the check should be visible.
• Invisible — no interface at all: the check runs in the background on behavioural signals.

The challenge is not a separate mode but an extra step. It appears only when a request looks suspicious, and regular visitors never see it.

Embedding

Add the loader and the widget container inside your form:

<script src="https://vintrex.pw/webcaptcha/api.js" defer></script>

<form method="post" action="/login">
  <div class="vintrex-captcha" data-sitekey="YOUR_SITE_KEY" data-action="login"></div>
  <button type="submit">Log in</button>
</form>

After a successful check the widget adds a hidden mitelis-captcha-response field with a token to the form. Send it to your server together with the rest of the data and verify it with a request to the WebCaptcha API using your secret key — the secret must never reach the browser.

If you need full control over the widget lifecycle, use the JavaScript API:

const id = window.mitelisCaptcha.render("#captcha", {
  sitekey: "YOUR_SITE_KEY",
  action: "login",
  callback: (token) => console.log("token", token),
  expiredCallback: () => console.log("token expired"),
});

// Show a fresh check, e.g. after a form error
window.mitelisCaptcha.reset(id);

Appearance

Colours, corner radius and border are configured per key, so the widget fits both dark and light sites. A live demo is available on the home page.