reCAPTCHA

GitLab leverages reCAPTCHA to protect against spam and abuse. GitLab displays the CAPTCHA form on the sign-up page to confirm that a real user, not a bot, is attempting to create an account.

Configuration

To use reCAPTCHA, first create a site and private key.

1. Go to the Google reCAPTCHA page.
2. To get reCAPTCHA v2 keys, fill in the form and select Submit.
3. Sign in to your GitLab server as an administrator.
4. On the left sidebar, at the bottom, select Admin.
5. Select Settings > Reporting.
6. Expand Spam and Anti-bot Protection.
7. In the reCAPTCHA fields, enter the keys you obtained in the previous steps.
8. Select the Enable reCAPTCHA checkbox.
9. To enable reCAPTCHA for logins via password, select the Enable reCAPTCHA for login checkbox.
10. Select Save changes.
11. To short-circuit the spam check and trigger the response to return recaptcha_html:
    1. Open app/services/spam/spam_verdict_service.rb.
    2. Change the first line of the #execute method to return CONDITIONAL_ALLOW.

Enable reCAPTCHA for user logins using the HTTP header

You can enable reCAPTCHA for user logins via password in the user interface or by setting the X-GitLab-Show-Login-Captcha HTTP header. For example, in NGINX, this can be done via the proxy_set_header configuration variable:

proxy_set_header X-GitLab-Show-Login-Captcha 1;

In Omnibus GitLab, this can be configured via /etc/gitlab/gitlab.rb:

nginx['proxy_set_headers'] = { 'X-GitLab-Show-Login-Captcha' => '1' }