diff --git a/Jenkinsfile b/Jenkinsfile
index 2606e74..1d098ab 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -2,7 +2,7 @@ pipeline {
   agent { label 'djb-vm' }
 
   triggers {
-    pollSCM('H/10 * * * *')
+    cron('H/10 * * * *')
   }
 
   options {
@@ -23,6 +23,8 @@ pipeline {
     CATALINA_HOME = '/prod/eapim/apache-tomcat-9.0.116'
     CATALINA_PID = '/prod/eapim/apigw/logs/catalina.pid'
     DEPLOY_HTTP_PORT = '39110'
+    REVISION_STATE_FILE = '.jenkins-last-deploy-revisions'
+    SHOULD_DEPLOY = 'true'
   }
 
   stages {
@@ -53,7 +55,53 @@ pipeline {
       }
     }
 
+    stage('Detect changes') {
+      steps {
+        script {
+          int status = sh(
+            returnStatus: true,
+            script: '''
+              set -eu
+              current_file="$(mktemp)"
+              {
+                printf 'eapim-online %s\\n' "$(git rev-parse HEAD)"
+                for REPO in elink-online-core elink-online-transformer elink-online-common elink-online-emsclient elink-online-core-jpa; do
+                  printf '%s %s\\n' "$REPO" "$(git -C "$REPO" rev-parse HEAD)"
+                done
+              } | sort > "$current_file"
+
+              if [ -f "$REVISION_STATE_FILE" ] && cmp -s "$current_file" "$REVISION_STATE_FILE"; then
+                echo "No repository changes detected. Skipping build and deploy."
+                echo "--- current revisions ---"
+                cat "$current_file"
+                rm -f "$current_file"
+                exit 10
+              fi
+
+              echo "Repository changes detected. Build and deploy will run."
+              echo "--- previous revisions ---"
+              [ -f "$REVISION_STATE_FILE" ] && cat "$REVISION_STATE_FILE" || echo "(none)"
+              echo "--- current revisions ---"
+              cat "$current_file"
+              mv "$current_file" .jenkins-current-deploy-revisions
+            '''
+          )
+          if (status == 10) {
+            env.SHOULD_DEPLOY = 'false'
+            currentBuild.description = 'No repo changes'
+          } else if (status != 0) {
+            error "Revision change detection failed with status ${status}"
+          } else {
+            env.SHOULD_DEPLOY = 'true'
+          }
+        }
+      }
+    }
+
     stage('Verify toolchain') {
+      when {
+        expression { env.SHOULD_DEPLOY == 'true' }
+      }
       steps {
         sh '''
           set -eu
@@ -64,6 +112,9 @@ pipeline {
     }
 
     stage('Build WAR') {
+      when {
+        expression { env.SHOULD_DEPLOY == 'true' }
+      }
       steps {
         sh 'gradle clean build -x test --no-daemon'
       }
@@ -81,6 +132,9 @@ pipeline {
     }
 
     stage('Stop Tomcat') {
+      when {
+        expression { env.SHOULD_DEPLOY == 'true' }
+      }
       steps {
         sh '''
           set +e
@@ -99,6 +153,9 @@ pipeline {
     }
 
     stage('Deploy ROOT.war') {
+      when {
+        expression { env.SHOULD_DEPLOY == 'true' }
+      }
       steps {
         sh '''
           set -eu
@@ -111,6 +168,9 @@ pipeline {
     }
 
     stage('Start Tomcat and readiness') {
+      when {
+        expression { env.SHOULD_DEPLOY == 'true' }
+      }
       steps {
         sh '''
           set -eu
@@ -162,4 +222,19 @@ pipeline {
       }
     }
   }
+
+  post {
+    success {
+      script {
+        if (env.SHOULD_DEPLOY == 'true') {
+          sh '''
+            set -eu
+            if [ -f .jenkins-current-deploy-revisions ]; then
+              mv .jenkins-current-deploy-revisions "$REVISION_STATE_FILE"
+            fi
+          '''
+        }
+      }
+    }
+  }
 }