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CAPTCHA Setup

September 15, 2026

A captcha is used to safeguard the application from brute-force attacks on user accounts and for protection of web mode from automatic creation of interviews.

Setting up a CAPTCHA is one of the steps of post installation configuration of a Survey Solutions server.

Survey Solutions may utilize a built-in (hosted) implementation of captcha (default) or an external reCAPTCHA provided by Google (to be configured as per instructions below).

To take advantage of the more secure reCAPTCHA implementation by Google, you need to set it up in the Google reCAPTCHA admin and record the 2 issued keys into your configuration file.

  • Navigate to creation page to register a new captcha and log in with your Google account. Note that clicking on the ℹ️-icons will give you helpful hints on how to fill out that form.
  • Specify a name for your CAPTCHA to distinguish it from other ones you may have. This name is not used by Survey Solutions and is not visible to your site’s visitors.
  • Select whether you want to register v2 (challenge) or v3 (score-based) type of reCAPTCHA.
  • Specify your public DNS name that is configured in Survey Solutions BaseUrl property for the site name. Do not include the protocol ("https://") or port (such as “:443”, or “:9700”) in this field. Note that a reCAPTCHA registered for a domain will also be registered for its subdomains.
  • Additional settings and analytics on the use of the created reCAPTCHA is available via the Google Cloud platform.

After you click the Submit button you will see a page where you can copy the necessary site key and secret key. Then add the following content into your appsettings.Production.ini file:

For reCAPTCHA v2:
[Captcha]
CaptchaType=Recaptcha
SecretKey=%Your secret key%
SiteKey=%Your site key%
Version=v2
For reCAPTCHA v3:
[Captcha]
CaptchaType=Recaptcha
SecretKey=%Your secret key%
SiteKey=%Your site key%
Version=v3
"RecaptchaV3MinimumScore": 0.5

Note that the parameter CaptchaType can be either of the following: None, Recaptcha (this is reCAPTCHA v2), RecaptchaV3, Hosted.

For reCAPTCHA v3 adjust the parameter RecaptchaV3MinimumScore to a value between 0.00 and 1.00. Values closer to 1 indicate confidence of user being a human, while score values closer to 0 indicate confidence of user being a bot. False detections are possible. You may need to monitor site traffic data and revise this parameter to optimize.

More information

See:

  • CAPTCHA - description of what a CAPTCHA may look like for a user

  • Autolock - description of accounts autolocking.

  • reCAPTCHA v3 - developer’s documentation at Google’s site.

  • reCAPTCHA v2 - developer’s documentation at Google’s site.