diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a26626838..578947491 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,4 +1,4 @@
-name: CI
+name: Tests
 
 on: [push, pull_request]
 
@@ -62,3 +62,5 @@ jobs:
         run: yarn install --frozen-lockfile --non-interactive
       - name: Run tests
         run: bundle exec rails test
+      - name: Run system tests
+        run: bundle exec rails test:system
diff --git a/Gemfile b/Gemfile
index 935e341f0..98b174175 100644
--- a/Gemfile
+++ b/Gemfile
@@ -91,10 +91,12 @@ group :development do
 end
 
 group :test do
+  gem 'capybara'
   gem 'committee'
   gem 'minitest'
   gem 'minitest-reporters'
   gem 'rails-controller-testing'
+  gem 'selenium-webdriver'
   gem 'vcr'
   gem 'webmock'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 5e606b21f..0f8b3d923 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -111,7 +111,7 @@ GEM
       activerecord (>= 4.0)
     autoprefixer-rails (10.4.13.0)
       execjs (~> 2)
-    base64 (0.1.2)
+    base64 (0.3.0)
     bcp47_spec (0.2.1)
     bcrypt (3.1.22)
     benchmark (0.5.0)
@@ -135,6 +135,15 @@ GEM
       railties (>= 3.1)
     builder (3.3.0)
     byebug (11.1.3)
+    capybara (3.40.0)
+      addressable
+      matrix
+      mini_mime (>= 0.1.3)
+      nokogiri (~> 1.11)
+      rack (>= 1.6.0)
+      rack-test (>= 0.6.3)
+      regexp_parser (>= 1.5, < 3.0)
+      xpath (~> 3.2)
     case_transform (0.2)
       activesupport
     cgi (0.5.1)
@@ -425,7 +434,7 @@ GEM
     orm_adapter (0.5.0)
     ostruct (0.6.3)
     parallel (1.23.0)
-    parser (3.2.2.3)
+    parser (3.3.11.1)
       ast (~> 2.4.1)
       racc
     pg (1.5.6)
@@ -624,12 +633,11 @@ GEM
       faraday (>= 0.9, < 3, != 2.0.0)
     rss (0.3.0)
       rexml
-    rubocop (1.56.1)
-      base64 (~> 0.1.1)
+    rubocop (1.57.2)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
       parallel (~> 1.10)
-      parser (>= 3.2.2.3)
+      parser (>= 3.2.2.4)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.8, < 3.0)
       rexml (>= 3.2.5, < 4.0)
@@ -643,6 +651,7 @@ GEM
       faraday (>= 1)
       faraday-multipart (>= 1)
     ruby-progressbar (1.13.0)
+    rubyzip (3.3.0)
     safely_block (0.4.0)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
@@ -661,6 +670,12 @@ GEM
       tilt
     scanf (1.0.0)
     securerandom (0.4.1)
+    selenium-webdriver (4.44.0)
+      base64 (~> 0.2)
+      logger (~> 1.4)
+      rexml (~> 3.2, >= 3.2.5)
+      rubyzip (>= 1.2.2, < 4.0)
+      websocket (~> 1.0)
     sentry-rails (5.11.0)
       railties (>= 5.0)
       sentry-ruby (~> 5.11.0)
@@ -803,6 +818,7 @@ GEM
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
     webrick (1.9.2)
+    websocket (1.2.11)
     websocket-driver (0.8.0)
       base64
       websocket-extensions (>= 0.1.0)
@@ -810,6 +826,8 @@ GEM
     whenever (1.0.0)
       chronic (>= 0.6.3)
     will_paginate (4.0.0)
+    xpath (3.2.0)
+      nokogiri (~> 1.8)
     yaml-ld (0.0.3)
       json-ld (~> 3.3)
       psych (>= 3.3)
@@ -833,6 +851,7 @@ DEPENDENCIES
   bootstrap-sass
   bootstrap-tab-history-rails
   byebug
+  capybara
   committee
   country_select
   devise
@@ -883,6 +902,7 @@ DEPENDENCIES
   ruby-openai
   sass-rails
   sassc-rails
+  selenium-webdriver
   sentry-rails
   sentry-ruby
   sentry-sidekiq
diff --git a/test/application_system_test_case.rb b/test/application_system_test_case.rb
new file mode 100644
index 000000000..38c58b5fe
--- /dev/null
+++ b/test/application_system_test_case.rb
@@ -0,0 +1,8 @@
+require 'test_helper'
+
+class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
+  driven_by :selenium, using: :headless_chrome, screen_size: [1400, 1400] do |options|
+    options.add_argument('--no-sandbox')
+    options.add_argument('--disable-dev-shm-usage')
+  end
+end
diff --git a/test/system/events_calendar_system_test.rb b/test/system/events_calendar_system_test.rb
new file mode 100644
index 000000000..34913d8f8
--- /dev/null
+++ b/test/system/events_calendar_system_test.rb
@@ -0,0 +1,26 @@
+require 'application_system_test_case'
+
+class EventsCalendarSystemTest < ApplicationSystemTestCase
+  test 'calendar tab loads and renders events with javascript' do
+    freeze_time(Time.utc(2026, 5, 20, 12, 0, 0)) do
+      Event.create!(
+        title: 'System calendar event',
+        url: 'http://example.com/system-calendar-event',
+        user: users(:regular_user),
+        content_provider: content_providers(:goblet),
+        timezone: 'UTC',
+        start: Time.now.beginning_of_month + 10.days,
+        end: Time.now.beginning_of_month + 10.days + 2.hours,
+        city: 'Manchester',
+        country: 'United Kingdom'
+      )
+
+      visit events_path
+
+      within('.index-display-options') { click_link 'Calendar' }
+
+      assert_selector('#events_calendar #calendar.simple-calendar')
+      assert_selector('#events_calendar a.clear-both', text: 'System calendar event')
+    end
+  end
+end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 17218b588..8d6583b3f 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -35,6 +35,7 @@
 VCR.configure do |config|
   config.cassette_library_dir = 'test/vcr_cassettes'
   config.hook_into :webmock
+  config.ignore_localhost = true
   # config.allow_http_connections_when_no_cassette = true
 end