Glossary · Data collection
CAPTCHA
A CAPTCHA — Completely Automated Public Turing test to tell Computers and Humans Apart — is a challenge a website presents to decide whether a request comes from a person or from software, ranging from distorted text and image selection to audio prompts and invisible checks on behaviour.
Reviewed 30 Oct 2026
Types of CAPTCHA
| Type | What the visitor sees |
|---|---|
| Text | Distorted letters or numbers to type in |
| Image | Pictures to select or compare |
| Audio | Spoken, distorted characters or words |
| Logic | A simple maths, word or spatial puzzle |
| Non-interactive | Nothing, or a checkbox: the site scores behaviour and context in the background, sometimes with hidden form fields only bots fill in |
The categories follow the W3C's review of CAPTCHA approaches.
Why sites use them
To keep automated traffic away from forms and actions where it does harm: account sign-ups, logins, comment spam, ticket and stock grabbing, and expensive searches. Many sites only show a challenge when something about a request looks unusual — its rate, its address's IP reputation or how the client behaves.
The accessibility cost
The W3C's note on the inaccessibility of CAPTCHA documents how visual tests exclude blind and low-vision users, audio alternatives exclude deaf and hard-of-hearing users, and distorted text burdens people with dyslexia or cognitive disabilities. It also observes that CAPTCHAs are becoming less effective against bots, which is one reason sites move to non-interactive checks.
What a CAPTCHA means for automated collection
A challenge is the site saying it does not want automated access to that page or at that rate. The right response is to stop, slow down, check robots.txt and the terms, and look for an official feed or API. ARC sells IP addresses; it does not solve or route around CAPTCHAs, and automating anything behind a challenge is out of scope — see acceptable use and collecting travel data responsibly.
FAQ
Questions
Something not covered? Write to contact@arcproxies.io.
What does CAPTCHA stand for?
Completely Automated Public Turing test to tell Computers and Humans Apart. It is a test that a computer sets and marks, meant to be easy for people and hard for software.
Why do I see more CAPTCHAs on some networks?
Sites weigh the address a request comes from, along with request rate and behaviour. Addresses shared by many users, or with a history of automated traffic, are challenged more often than a quiet home connection.
Do proxies solve CAPTCHAs?
No. A proxy changes the network address a request comes from and nothing else. ARC does not offer CAPTCHA solving, and a challenge page is a signal to slow down or stop, not an obstacle to automate.
What is an invisible CAPTCHA?
A check that runs without asking the visitor to do anything, scoring signals such as interaction patterns and context in the background and only escalating to a visible challenge when the score is low.
Sources & review
Last reviewed by the ARC Proxies team. Prices are read from the live catalog at build time.
In practice