How reCAPTCHA Invisible Works and How to Solve It

By Irina

Published at Feb 27, 2026

Invisible reCAPTCHA is a variant of reCAPTCHA v2 that eliminates the "I'm not a robot" checkbox. Instead of requiring a user click, it fires automatically when a form is submitted or a button is clicked. Google's risk analysis runs in the background — if the user appears human, the form proceeds without interruption. If the score is suspicious, an image challenge pops up.

For automation, this creates a specific problem: there is no visible element to interact with, and the CAPTCHA may trigger only during the form submit event.

How it works under the hood

Page load — the site loads api.js and renders an invisible widget (no visible UI)
User action — the user clicks a button or submits a form that triggers grecaptcha.execute()
Risk analysis — Google evaluates browser signals (mouse movement, browsing history, IP reputation)
Decision — if the user passes, Google calls the data-callback function with a token. If suspicious, an image challenge appears
Token verification — the site's backend verifies the token via siteverify

How to detect invisible reCAPTCHA on a page

<!-- Pattern 1: div with data-size="invisible" -->
<div class="g-recaptcha" data-sitekey="6LdKlZEU..." data-size="invisible" data-callback="onSubmit"></div>

<!-- Pattern 2: button with data-sitekey -->
<button class="g-recaptcha" data-sitekey="6LdKlZEU..." data-callback="onSubmit" data-action="submit">Submit</button>

<!-- Pattern 3: programmatic bind -->
<script>
  grecaptcha.render('submit-btn', {
    sitekey: '6LdKlZEU...',
    callback: onSubmit,
    size: 'invisible'
  });
</script>

Key indicators:

data-size="invisible" or size: 'invisible' in render()
No visible checkbox on the page
data-callback attribute pointing to a JavaScript function
reCAPTCHA badge in the bottom-right corner (can be hidden via CSS)

Invisible vs standard v2

Feature	Standard v2	Invisible v2
User interaction	Required (click checkbox)	None (fires on button click)
Visible widget	Checkbox	No visible element
Image challenge	Always (if not auto-passed)	Only when suspicious
Token delivery	Hidden field or callback	Almost always callback
Detection	Look for checkbox	`data-size="invisible"`
CaptchaAI param	`invisible=0` (default)	`invisible=1`

How to solve it with CaptchaAI

The solve flow is identical to standard v2 with one addition:

import requests
import time

# Submit with invisible=1
response = requests.get("https://ocr.captchaai.com/in.php", params={
    "key": "YOUR_API_KEY",
    "method": "userrecaptcha",
    "googlekey": "6LdKlZEUAAAAAPoxm...",
    "pageurl": "https://example.com/signup",
    "invisible": 1,
    "json": 1
})

task_id = response.json()["request"]

# Poll
for _ in range(40):
    time.sleep(5)
    result = requests.get("https://ocr.captchaai.com/res.php", params={
        "key": "YOUR_API_KEY", "action": "get", "id": task_id, "json": 1
    }).json()
    if result.get("status") == 1:
        token = result["request"]
        break

# Inject via callback (not hidden field)
# driver.execute_script(f"onSubmit('{token}');")

The critical difference is token injection: call the callback function instead of filling the hidden field. See How to Solve reCAPTCHA Invisible Using API for the full tutorial.

FAQ

Can invisible reCAPTCHA show image challenges?

Yes. If Google's risk analysis flags the user as suspicious, it displays an image challenge — exactly like standard v2.

How does invisible reCAPTCHA differ from v3?

Invisible v2 is triggered by a user action (button click) and may show a challenge. v3 runs on every page load, never shows a challenge, and only returns a score.

Why do I need invisible=1 for CaptchaAI?

Without it, CaptchaAI generates a standard v2 token. Some invisible implementations reject standard tokens because they expect a different verification context.

Can invisible reCAPTCHA be detected by my scraper without a browser?

Yes. Check the page HTML source for data-size="invisible" or buttons with data-sitekey. These are present in the raw HTML before any JavaScript executes.