Captcha
Captcha is an Alibaba Cloud compute service designed to authenticate users by distinguishing between human visitors and automated computer programs. It serves as a critical security layer for applications, preventing bots from abusing online forms or login pages. By verifying that interactions originate from real people, it helps maintain the integrity of digital services against automated attacks and spam.
Choose this solution when you need a straightforward, pay-as-you-go mechanism to separate humans from machines without upfront commitments. Be aware that there is no free tier available, meaning every verification request incurs a direct cost. This usage-based pricing model requires careful monitoring to avoid unexpected charges as traffic volume increases.