CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a challenge-response test designed to distinguish human users from bots, commonly appearing as image puzzles, checkboxes, or logic questions before granting access to a page or action. Websites deploy CAPTCHAs specifically to block automated scraping and account creation.

Modern CAPTCHA systems increasingly work invisibly in the background: reCAPTCHA v3 scores each visitor without showing a challenge and leaves the response to the site, while invisible hCaptcha only presents a challenge when a visitor meets its challenge criteria. A clean IP reputation and natural browsing behavior can avoid triggering a CAPTCHA at all, rather than needing to solve one, this is part of why IP reputation can affect how often a scraper encounters CAPTCHAs in the first place.

Whether a challenge appears at all depends largely on how suspicious the underlying traffic already looks. A visitor with a clean IP and natural browsing behavior may never see a CAPTCHA at all, while one with a flagged IP is more likely to be challenged.

Some operations route CAPTCHA challenges to a CAPTCHA solving service rather than avoiding them entirely, which trades a small per-solve cost for not having to keep an IP and browsing pattern clean enough to dodge the challenge in the first place.