Solving reCAPTCHA v3

reCAPTCHA v3

We've been solving reCAPTCHA v3 for 3 weeks and are now ready to share some stats.

First, a few words about reCAPTCHA v3

As you probably know, reCAPTCHA v3 doesn't require any kind of solving as before, instead it measures a user's score and then passes it to the site's backend. This score is based on the information google.com is gathering about the user. The score ranges from 0.1 to 0.9 and may vary for different sites.

We've made a few experiments and conclude that if someone has 0.1 on one site, it is 90% likely that he will get the same score of 0.1 for other sites.

How does the solving of 2captcha.com works

Every worker is given a test captcha which gives us a score. We record this score for every worker. When a customer requests solving of reCAPTCHA v3 with some minimum score requirement we send those requests to the workers with appropriate scores only. As a result, 80 to 90% of solving will hit the required score.

Here is an example of a request for reCAPTCHA v3 solving

http://2captcha.com/in.php?key=APIKEY&method=userrecaptcha&googlekey=googlekey&pageurl=https://site.com/page.html&version=v3&action=verify&min_score=0.5

It is almost the same as reCAPTCHA v2 but has a few new parameters:

  • version=v3 indicates that it is reCAPTCHA v3

  • action=verify indicates the name of the action on the page

  • min_score=0.3 indicates the minimum score the customer needs

Pricing

For the testing period we set the same price as reCAPTCHA v2

Refunds for invalid tokens

It's complicated. When a customer complains about graphic captcha we can solve it again and see whether the solving was correct or not. When a customer complains about reCAPTCHA v2 we can look up the complaint stats and see if some workers are making deliberate mistakes, and then refund for wrongly solved captchas.

reCAPTCHA v3, on the other hand, is different: one worker could have different scores for different sites. One site will get a 0.1 score and another will get a 0.5 score for the same worker.

We still support a complaint message reportbad which you should send in case a site refuses the token:

http://2captcha.com/res.php?key=YOUR_API_KEY&action=reportbad&id=CAPTCHA_ID

But we also added a new reportgood message for the correct token:

http://2captcha.com/res.php?key=YOUR_API_KEY&action=reportgood&id=CAPTCHA_ID

When we receive this reportgood message we add the appropriate worker to the WhiteList for your account so all your requests of reCAPTCHA V3 will only be distributed among the workers from your WhiteList. In future we plan to refund only the customers who send us reportgood messages. Please note that we do not refund for reportbad messages at the moment, but we probably will do so soon.

What min_score should you use?

For now we support only 0.1, 0.3 and 0.9 scores. The sites we tested accept both 0.9 and 0.3 scores and none of them accept 0.1. That's why we suggest that customers start from the score of 0.3 and increase it to 0.9 only if more than 50% of tokens are denied. Please note that there is twice as many workers with the score of 0.3 than those with the score of 0.9.