diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f9f1168..e3783e5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -2,13 +2,17 @@ name: Build
 
 on:
   push:
-    branches: [ "master" ]
+    branches:
+      - master
   pull_request:
-    branches: [ "master" ]
+    types: [opened, synchronize, reopened]
   schedule:
     - cron: "0 3 * * 0-6"
   workflow_dispatch:
 
+permissions:
+  checks: write
+
 jobs:
   build:
 
@@ -16,18 +20,27 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
+
       - name: Set up JDK 17
         uses: actions/setup-java@v3
         with:
           java-version: '17'
           distribution: 'temurin'
           cache: maven
+
       - name: Compile and Unit tests (headless for GUI)
         uses: GabrielBB/xvfb-action@v1.6
         with:
           run: mvn clean org.jacoco:jacoco-maven-plugin:prepare-agent install
+
       - name: Quality gate
         run: mvn --batch-mode org.sonarsource.scanner.maven:sonar-maven-plugin:sonar
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
+
+      - name: Run mutation testing
+        run: mvn clean test-compile org.pitest:pitest-maven:mutationCoverage
+
+      - name: Compute and check tests strength
+        uses: teemoo7/mutation-testing-report-action@v0.1
diff --git a/pom.xml b/pom.xml
index 2071ca1..fc12d28 100644
--- a/pom.xml
+++ b/pom.xml
@@ -30,6 +30,7 @@
     <maven.plugin.checkstyle.version>3.2.0</maven.plugin.checkstyle.version>
     <maven.plugin.failsafe.version>3.0.0-M7</maven.plugin.failsafe.version>
     <maven.plugin.jacoco.version>0.8.8</maven.plugin.jacoco.version>
+    <maven.plugin.pitest.version>1.9.0</maven.plugin.pitest.version>
     <maven.plugin.project-info-reports.version>3.4.1</maven.plugin.project-info-reports.version>
     <maven.plugin.site.version>4.0.0-M3</maven.plugin.site.version>
     <maven.plugin.spotbugs.version>4.7.2.0</maven.plugin.spotbugs.version>
@@ -253,6 +254,34 @@
           </execution>
         </executions>
       </plugin>
+
+      <plugin>
+        <groupId>org.pitest</groupId>
+        <artifactId>pitest-maven</artifactId>
+        <version>${maven.plugin.pitest.version}</version>
+        <configuration>
+          <targetClasses>
+            <targetClass>ch.teemoo.bobby.*</targetClass>
+          </targetClasses>
+          <targetTests>
+            <targetTest>ch.teemoo.bobby.*</targetTest>
+          </targetTests>
+          <excludedClasses>
+            <param>*.gui.*</param>
+          </excludedClasses>
+          <excludedTestClasses>
+            <param>*.gui.*</param>
+            <param>*IT</param>
+            <param>*SwingTest</param>
+            <param>*FactoryTest</param>
+          </excludedTestClasses>
+          <outputFormats>
+            <outputFormat>XML</outputFormat>
+          </outputFormats>
+          <timestampedReports>false</timestampedReports>
+          <threads>2</threads>
+        </configuration>
+      </plugin>
     </plugins>
   </build>