diff --git a/inventory/php/group_vars/all.yml.skeleton b/inventory/php/group_vars/all.yml.skeleton
index bc9c171..bdbf9a8 100644
--- a/inventory/php/group_vars/all.yml.skeleton
+++ b/inventory/php/group_vars/all.yml.skeleton
@@ -35,6 +35,9 @@ github_secret:
 bugs_magic_cookie: 
 flickr_api_token: 
 
+# Bunny CDN account API key, used by update-www to purge the CDN cache
+bunny_api_key:
+
 # OhDearHealthChecks
 ohdear_secret: 
 
diff --git a/roles/properties/www/tasks/deploy.yml b/roles/properties/www/tasks/deploy.yml
index 1ec3140..04804ce 100644
--- a/roles/properties/www/tasks/deploy.yml
+++ b/roles/properties/www/tasks/deploy.yml
@@ -9,6 +9,9 @@
     src: templates/update-www
     dest: /local/systems/update-www
     mode: "700"
+  vars:
+    bunny_purge_urls:
+      - "https://www.php.net/pre-release-builds.php*"
 
 - name: Create a cron job to run every 5 minutes
   cron:
diff --git a/roles/properties/www/templates/update-www b/roles/properties/www/templates/update-www
index 3c254f3..2a2ce58 100644
--- a/roles/properties/www/templates/update-www
+++ b/roles/properties/www/templates/update-www
@@ -1,7 +1,22 @@
 #!/bin/sh
 
-rsync -rlptDC --timeout=600 --delete --delete-after \
+# export tokens
+export BUNNY_API_KEY="{{ bunny_api_key }}"
+
+CHANGES=$(rsync -rlptDC --timeout=600 --delete --delete-after --itemize-changes \
     --include='distributions/*.exe' --include='manual/en/' \
     --include='manual/en/**' --include='manual/*.php' \
     --include='manual/**' {{ rsync_address }}::phpweb \
-    {{ www_docroot }}
+    {{ www_docroot }})
+
+# Bust the Bunny CDN cache, but only when rsync actually pulled new
+# content (avoids purging on every 5-minute run). The Bunny purge API
+# takes a single URL per request, so each one is a separate call.
+if [ -n "$CHANGES" ]; then
+    for url in {% for url in bunny_purge_urls %}'{{ url }}' {% endfor %}; do
+        curl --fail --silent --show-error --request POST \
+            --url "https://api.bunny.net/purge?url=${url}" \
+            --header "AccessKey: ${BUNNY_API_KEY}"
+    done
+fi
+