diff --git a/Gemfile b/Gemfile
index d9e5029d2e..46a3c3bd29 100644
--- a/Gemfile
+++ b/Gemfile
@@ -142,6 +142,7 @@ gem "faraday"
 gem "private_address_check"
 
 gem 'newrelic_rpm'
+gem 'invisible_captcha'
 
 group :production, :staging do
   gem 'sd_notify' # For better Systemd process management. Used by Puma.
diff --git a/Gemfile.lock b/Gemfile.lock
index 8974a3d8ad..fa548b1e02 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -343,6 +343,8 @@ GEM
       ruby-vips (>= 2.0.17, < 3)
     immigrant (0.3.6)
       activerecord (>= 3.0)
+    invisible_captcha (2.1.0)
+      rails (>= 5.2)
     io-console (0.7.1)
     ipaddress (0.8.3)
     irb (1.11.0)
@@ -857,6 +859,7 @@ DEPENDENCIES
   i18n-js (~> 3.9.0)
   image_processing
   immigrant
+  invisible_captcha
   jquery-rails (= 4.4.0)
   jquery-ui-rails (~> 4.2)
   json