Every website has its own bot detection system (often built by the software engineers at the company) ranging from simple to complex. The threshold for what is considered “abnormal” behavior is different for every site. Simplex’s anti-stealth measures usually prevent CAPTCHAs from showing up on initial automation tests. There are two reasons that CAPTCHAs are generally triggered.
  1. Your automation fails often in a short timeframe, or you log into an account a far greater number of times than is generally seen by humans on the site.
  2. The website serves CAPTCHAs to almost every single user. This is rarer (it can be expensive for the company hosting the site), but we’ve seen it before.
Simplex has a built-in CAPTCHA solver that can solve most CAPTCHAs automatically. It’s enabled by default in all sessions. When stress testing your automations before moving into production (running 100 concurrent sessions, for example), you may see CAPTCHAs more often. You can use Simplex’s captcha_exists and wait_for_captcha functions to handle CAPTCHAs in your automations. You can see an example in the CAPTCHA Handling section.