Identify the captcha type

Choosing the right task type starts with recognizing the captcha. The most reliable way is to open the browser’s developer tools (F12) and see in the Network panel which captcha script the page loads; you can also tell by appearance.

Quick reference

What you see	What it is	Task type
An “I’m not a robot” checkbox	reCAPTCHA v2	reCAPTCHA v2
No checkbox; an image challenge appears after you click submit; a small reCAPTCHA badge in the corner	Invisible reCAPTCHA v2 (or v3)	See “reCAPTCHA versions” below
No interaction at all; only the reCAPTCHA badge	reCAPTCHA v3	reCAPTCHA v3
An “I am human” checkbox; image challenges branded hCaptcha	hCaptcha	hCaptcha
A Cloudflare widget inside a form; the page stays put after the check	Cloudflare Turnstile	Turnstile
The whole page shows “Just a moment…” / “Checking your connection” and then redirects	Cloudflare challenge page	Cloudflare challenge page
Arkose Labs puzzles (such as “Pick the image that is the correct way up”)	FunCaptcha	FunCaptcha
An image of distorted letters and digits	Text captcha	Image to text

reCAPTCHA versions

Search the Network panel for api.js or enterprise.js:

Script loaded	Version
recaptcha/api.js with no render parameter or render=explicit	v2
As above, and the anchor request URL contains size=invisible	Invisible v2: add "isInvisible": true
recaptcha/api.js?render=SITE_KEY (render is not explicit)	v3
recaptcha/enterprise.js with no render parameter or render=explicit	v2 Enterprise
recaptcha/enterprise.js?render=SITE_KEY	v3 Enterprise

Examples:

https://www.google.com/recaptcha/api.js?onload=onloadcallback&render=explicit   → v2
https://www.google.com/recaptcha/api.js?render=6LdyC2cUAAAAACGuDKpXeDorzUDWXmdqeg-xy696   → v3
https://www.google.com/recaptcha/enterprise.js?render=explicit   → v2 Enterprise

Invisible v2 sometimes passes only with a v3 type; try both.

You can also run this in the browser console. It lists every reCAPTCHA on the page with its version, site key, page URL and callback:

find-recaptcha-clients.js

// Paste into the browser DevTools console on a page with reCAPTCHA, then run findRecaptchaClients().
// Lists every reCAPTCHA on the page: version (V2/V3), sitekey, page URL and the callback function.
function findRecaptchaClients() {
  if (typeof ___grecaptcha_cfg === 'undefined') return [];
  return Object.entries(___grecaptcha_cfg.clients).map(([cid, client]) => {
    const data = { id: cid, version: cid >= 10000 ? 'V3' : 'V2' };
    const objects = Object.entries(client).filter(([, value]) => value && typeof value === 'object');
    objects.forEach(([toplevelKey, toplevel]) => {
      const found = Object.entries(toplevel).find(
        ([, value]) => value && typeof value === 'object' && 'sitekey' in value && 'size' in value,
      );
      if (toplevel instanceof HTMLElement && toplevel.tagName === 'DIV') data.pageurl = toplevel.baseURI;
      if (found) {
        const [sublevelKey, sublevel] = found;
        data.sitekey = sublevel.sitekey;
        const callbackKey = data.version === 'V2' ? 'callback' : 'promise-callback';
        const callback = sublevel[callbackKey];
        if (!callback) {
          data.callback = null;
          data.function = null;
        } else {
          data.function = callback;
          const keys = [cid, toplevelKey, sublevelKey, callbackKey].map((key) => `['${key}']`).join('');
          data.callback = `___grecaptcha_cfg.clients${keys}`;
        }
      }
    });
    return data;
  });
}

findRecaptchaClients();

Example output:

[
  {
    "id": "0",
    "version": "V2",
    "sitekey": "6Le-wvkSAAAAAPBMRTvw0Q4Muexq9bi0DJwx_mJ-",
    "function": "onSuccess",
    "callback": "___grecaptcha_cfg.clients['0']['l']['l']['callback']",
    "pageurl": "https://www.google.com/recaptcha/api2/demo"
  }
]

Google’s demo pages are useful for comparison: v2 https://www.google.com/recaptcha/api2/demo, invisible v2 https://www.google.com/recaptcha/api2/demo?invisible=true.

Turnstile vs the challenge page

Both come from Cloudflare, but they are different:

• Turnstile is a widget embedded in a page’s form. After verification it shows a check mark and the page stays where it is. The page loads challenges.cloudflare.com/turnstile/v0/api.js. Use Turnstile.
• The challenge page replaces the whole page with Cloudflare’s “Just a moment…” / “example.com needs to review the security of your connection” screen, which may also contain a widget; after passing, it redirects to the real page. The source contains __cf_chl_rt_tk or cdn-cgi/challenge-platform. Use Cloudflare challenge page.

If your program gets a 403 with “Just a moment…” but a browser opens the page directly, you’re probably only being blocked by TLS fingerprinting. A library that imitates a browser’s TLS fingerprint (such as curl_cffi) usually fixes it without solving anything.