It’s a test to determine whether the entity you’re interacting with is a computer or human. In other words, if that girl you’re trying to hook up with on Tinder is really a person, or just an elaborate chatbot that’ll try to shill an expensive webcam site. The main purpose of CAPTCHA tests is to filter human traffic from bots (yes, web scrapers are bots). They do so by presenting various challenges to website visitors. The challenges are designed to be easily solvable by humans but very hard to crack for computers. CAPTCHAs allows website administrators to curb unwelcome automated activities, such as spam, DDoS attacks, and sometimes web scraping.ĬAPTCHAs also have secondary purposes. Originally, they helped to digitize badly-scanned text passages that optical content recognition (OCR) technologies couldn’t crack.
Nowadays, we provide free labor for Google’s machine learning algorithms by labeling objects in images. How Do CAPTCHAs Work?ĬAPTCHAs function as a final test to determine if a website’s visitor is human or bot. They appear when a website detects unusual traffic then they present the visitor with a challenge. The exact configuration of a CAPTCHA depends on the webmaster: it can protect the whole website or specific pages. Sometimes, a page will always throw up a CAPTCHA, especially if it’s a registration, comment form, or checkout page. The main factors that cause a CAPTCHA are: But more often, it needs some kind of trigger to appear. These include unusual traffic, high number of connections from a single IP address, or the use of low quality datacenter IPs. The same is with corporate networks that share an IP address between many employees.įor example, VPN users see more CAPTCHAs than regular website visitors because VPNs get their IPs from a data center. A collection of parameters that evaluate your network and device. The most important are HTTP headers, user agent, TLS and TCP/IP data.