tencent cloud



Last updated: 2024-02-01 14:47:53

    What is TenDI Captcha?

    TenDI Captcha provides web and app developers with comprehensive multi-dimensional human verification services through trajectory analysis, characteristic identification, anti-emulator, and other security mechanisms. It safeguards business security in various scenarios like registration and login, marketing offers, commenting/posting/polling, and data protection.
    This service helps you solve the following security problems:
    Preventing credential stuffing attacks as well as bulk registration of multiple accounts by bots.
    Preventing click farming and coupon abuse by bots in campaigns.
    Preventing ad spamming, malicious bumping, and poll fraud.
    Preventing from website content and data theft by bots and crawlers.


    Slider CAPTCHA

    This feature allows users to quickly complete verification by simply sliding the knob. Its ease of use and powerful risk control make it suitable for most human verification scenarios.

    Graphic CAPTCHA

    Sequentially clicking on the shapes in the image can complete the verification process. This method is suitable for high-security scenarios.

    Audio CAPTCHA

    By playing the audio, users can complete verification by filling in the content of the audio. Voice verification has unique interaction and strong risk control ability, which is suitable for accessibility scenarios.

    Non-perception CAPTCHA

    Users does not need to answer questions, as the system intelligently assesses the user's risk situation and returns the verification result through the backend API. This is suitable for scenarios that require a high level of user experience.

    Smart verification

    This feature intelligently identifies user characteristics. It requests suspicious users to answer verification questions and allows trusted users to directly proceed. This can greatly improve the experience of human users. The verification process is as follows:

    Multi-dimensional defense

    During the verification, ten security protection mechanisms such as dynamic encryption, virtual machine reinforcement, and anti-emulator are used to defend against malicious activities of the black market.


    Disabled users can switch from common verification mode to accessibility mode conveniently. Captcha Service is in compliance with Web Content Accessibility Guidelines (WCAG) 2.1, which makes content more accessible to a wider range of users with disabilities, providing a more friendly and more interactive experience.

    Controllable risk control level

    TenDI Captcha supports three risk control levels — Loose, General, and Strict.

    Verification results

    TenDI Captcha automatically blocks malicious user requests using multiple defense approaches.
    To be verified
    Trusted user: Verification successful
    Malicious user: Verification blocked


    TenDI Captcha provides data that is updated every minute so that you can keep track of business security in real time.
    Load requests
    The number of times the client loads verification.
    Verification requests
    The number of verifications initiated after a user responds to the verification question.
    Verification requests passed
    The number of passed verifications.
    Verification requests blocked
    The number of blocked verification requests.
    Failed verifications for wrong responses
    The number of verifications blocked due to the wrong responses given by the user.
    Verifications blocked by security policies
    The number of verifications blocked by security policies.
    Requests to verify tickets
    The number of ticket verifications initiated by a server.
    Ticket verification requests passed
    The number of passed ticket verifications.
    Ticket verification requests blocked
    The number of blocked ticket verification requests.

    Use limits

    QPS limit

    1. Queries Per Second (QPS) is limited to 1,000 for ticket verification.
    2. When QPS exceeds 1,000 for the ticket verification API calls, an error is returned (RequestLimitExceeded).
    3. To change the limit, submit a ticket or contact us.


    If you have any questions when using the service, please see FAQs About Features.
    Contact Us

    Contact our sales team or business advisors to help your business.

    Technical Support

    Open a ticket if you're looking for further assistance. Our Ticket is 7x24 avaliable.

    7x24 Phone Support