diff --git a/pmd-ant/pom.xml b/pmd-ant/pom.xml
index bd264fd471..92156edb96 100644
--- a/pmd-ant/pom.xml
+++ b/pmd-ant/pom.xml
@@ -30,6 +30,18 @@
                     </offlineLinks>
                 </configuration>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.ant.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 
diff --git a/pmd-apex/pom.xml b/pmd-apex/pom.xml
index 6c875b3a87..7324f13452 100644
--- a/pmd-apex/pom.xml
+++ b/pmd-apex/pom.xml
@@ -55,6 +55,20 @@
                 <groupId>org.jetbrains.dokka</groupId>
                 <artifactId>dokka-maven-plugin</artifactId>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.lang.apex.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.apex.metrics.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.apex.rule.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pmd-cli/pom.xml b/pmd-cli/pom.xml
index 8e001b28ae..946c1a8d55 100644
--- a/pmd-cli/pom.xml
+++ b/pmd-cli/pom.xml
@@ -20,6 +20,21 @@
                     <suppressionsLocation>pmd-cli-checkstyle-suppressions.xml</suppressionsLocation>
                 </configuration>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.cli.internal</exclude>
+                            <exclude>net.sourceforge.pmd.cli.commands.internal</exclude>
+                            <exclude>net.sourceforge.pmd.cli.commands.mixins.internal</exclude>
+                            <exclude>net.sourceforge.pmd.cli.commands.typesupport.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pmd-core/pom.xml b/pmd-core/pom.xml
index bceb5e607f..67cd064514 100644
--- a/pmd-core/pom.xml
+++ b/pmd-core/pom.xml
@@ -76,6 +76,26 @@
                     <offlineLinks combine.self="override"></offlineLinks>
                 </configuration>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.internal</exclude>
+                            <exclude>net.sourceforge.pmd.cache.internal</exclude>
+                            <exclude>net.sourceforge.pmd.cpd.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.ast.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.rule.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.rule.xpath.internal</exclude>
+                            <exclude>net.sourceforge.pmd.properties.internal</exclude>
+                            <exclude>net.sourceforge.pmd.renderers.internal</exclude>
+                            <exclude>net.sourceforge.pmd.util.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pmd-doc/pom.xml b/pmd-doc/pom.xml
index 682b0a8720..10f70bd0e4 100644
--- a/pmd-doc/pom.xml
+++ b/pmd-doc/pom.xml
@@ -16,6 +16,22 @@
         <java.version>8</java.version>
     </properties>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.doc.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
     <profiles>
         <profile>
             <id>generate-rule-docs</id>
diff --git a/pmd-java/pom.xml b/pmd-java/pom.xml
index 7117e3fb63..dbc0c16c0a 100644
--- a/pmd-java/pom.xml
+++ b/pmd-java/pom.xml
@@ -122,6 +122,26 @@
                     <suppressionsLocation>pmd-java-checkstyle-suppressions.xml</suppressionsLocation>
                 </configuration>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.lang.java.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.ast.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.metrics.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.rule.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.rule.xpath.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.symbols.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.symbols.table.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.types.internal</exclude>
+                            <exclude>net.sourceforge.pmd.lang.java.types.ast.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pmd-kotlin/pom.xml b/pmd-kotlin/pom.xml
index 84b52a59d5..5ea491683a 100644
--- a/pmd-kotlin/pom.xml
+++ b/pmd-kotlin/pom.xml
@@ -63,6 +63,18 @@
                     </delimiters>
                 </configuration>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.lang.kotlin.rule.xpath.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 
diff --git a/pmd-modelica/pom.xml b/pmd-modelica/pom.xml
index 9294558039..58a4e48e2b 100644
--- a/pmd-modelica/pom.xml
+++ b/pmd-modelica/pom.xml
@@ -76,6 +76,18 @@
                     </execution>
                 </executions>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.lang.modelica.resolver.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pmd-plsql/pom.xml b/pmd-plsql/pom.xml
index 545480e663..ff0b7c7f6c 100644
--- a/pmd-plsql/pom.xml
+++ b/pmd-plsql/pom.xml
@@ -79,6 +79,18 @@
                     <suppressionsLocation>pmd-plsql-checkstyle-suppressions.xml</suppressionsLocation>
                 </configuration>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.lang.plsql.ast.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pmd-scala-modules/pmd-scala-common/pom.xml b/pmd-scala-modules/pmd-scala-common/pom.xml
index 498d3bdd46..13a68664ba 100644
--- a/pmd-scala-modules/pmd-scala-common/pom.xml
+++ b/pmd-scala-modules/pmd-scala-common/pom.xml
@@ -123,6 +123,18 @@
                         </offlineLinks>
                     </configuration>
                 </plugin>
+
+                <plugin>
+                    <groupId>com.github.siom79.japicmp</groupId>
+                    <artifactId>japicmp-maven-plugin</artifactId>
+                    <configuration>
+                        <parameter>
+                            <excludes combine.children="append">
+                                <exclude>net.sourceforge.pmd.lang.scala.internal</exclude>
+                            </excludes>
+                        </parameter>
+                    </configuration>
+                </plugin>
             </plugins>
         </pluginManagement>
     </build>
diff --git a/pmd-visualforce/pom.xml b/pmd-visualforce/pom.xml
index 5446e6956f..d361264c2d 100644
--- a/pmd-visualforce/pom.xml
+++ b/pmd-visualforce/pom.xml
@@ -74,6 +74,18 @@
                     </execution>
                 </executions>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.lang.visualforce.rule.security.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pmd-xml/pom.xml b/pmd-xml/pom.xml
index e9c3b895b3..3b48f67441 100644
--- a/pmd-xml/pom.xml
+++ b/pmd-xml/pom.xml
@@ -33,6 +33,18 @@
                     <escapeString>\</escapeString>
                 </configuration>
             </plugin>
+
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+                <configuration>
+                    <parameter>
+                        <excludes combine.children="append">
+                            <exclude>net.sourceforge.pmd.lang.xml.ast.internal</exclude>
+                        </excludes>
+                    </parameter>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>
diff --git a/pom.xml b/pom.xml
index 7aefbb6f6e..3e17adcd59 100644
--- a/pom.xml
+++ b/pom.xml
@@ -624,6 +624,30 @@
                         </lifecycleMappingMetadata>
                     </configuration>
                 </plugin>
+
+                <plugin>
+                    <groupId>com.github.siom79.japicmp</groupId>
+                    <artifactId>japicmp-maven-plugin</artifactId>
+                    <version>0.20.0</version>
+                    <configuration>
+                        <parameter>
+                            <breakBuildBasedOnSemanticVersioning>true</breakBuildBasedOnSemanticVersioning>
+                            <onlyModified>true</onlyModified>
+                            <excludes>
+                                <exclude>@net.sourceforge.pmd.annotation.InternalApi</exclude>
+                            </excludes>
+                        </parameter>
+                    </configuration>
+                    <executions>
+                        <execution>
+                            <id>japicmp</id>
+                            <phase>verify</phase>
+                            <goals>
+                                <goal>cmp</goal>
+                            </goals>
+                        </execution>
+                    </executions>
+                </plugin>
             </plugins>
         </pluginManagement>
         <plugins>
@@ -728,6 +752,11 @@
                     </execution>
                 </executions>
             </plugin>
+            <!-- Enable japicmp for all modules by default -->
+            <plugin>
+                <groupId>com.github.siom79.japicmp</groupId>
+                <artifactId>japicmp-maven-plugin</artifactId>
+            </plugin>
         </plugins>
     </build>
 
@@ -1183,6 +1212,7 @@
                 <cpd.skip>true</cpd.skip>
                 <cyclonedx.skip>true</cyclonedx.skip>
                 <dokka.skip>true</dokka.skip>
+                <japicmp.skip>true</japicmp.skip>
             </properties>
         </profile>