diff --git a/scm-webapp/src/main/java/sonia/scm/api/rest/GroupAlreadyExistsExceptionMapper.java b/scm-webapp/src/main/java/sonia/scm/api/rest/GroupAlreadyExistsExceptionMapper.java
new file mode 100644
index 0000000000..43c0d1ff32
--- /dev/null
+++ b/scm-webapp/src/main/java/sonia/scm/api/rest/GroupAlreadyExistsExceptionMapper.java
@@ -0,0 +1,16 @@
+package sonia.scm.api.rest;
+
+import sonia.scm.group.GroupAlreadyExistsException;
+
+import javax.ws.rs.core.Response;
+import javax.ws.rs.core.Response.Status;
+import javax.ws.rs.ext.ExceptionMapper;
+import javax.ws.rs.ext.Provider;
+
+@Provider
+public class GroupAlreadyExistsExceptionMapper implements ExceptionMapper<GroupAlreadyExistsException> {
+  @Override
+  public Response toResponse(GroupAlreadyExistsException exception) {
+    return Response.status(Status.CONFLICT).build();
+  }
+}
diff --git a/scm-webapp/src/main/java/sonia/scm/api/rest/UserAlreadyExistsExceptionMapper.java b/scm-webapp/src/main/java/sonia/scm/api/rest/UserAlreadyExistsExceptionMapper.java
new file mode 100644
index 0000000000..ef0cc8b0a4
--- /dev/null
+++ b/scm-webapp/src/main/java/sonia/scm/api/rest/UserAlreadyExistsExceptionMapper.java
@@ -0,0 +1,16 @@
+package sonia.scm.api.rest;
+
+import sonia.scm.user.UserAlreadyExistsException;
+
+import javax.ws.rs.core.Response;
+import javax.ws.rs.core.Response.Status;
+import javax.ws.rs.ext.ExceptionMapper;
+import javax.ws.rs.ext.Provider;
+
+@Provider
+public class UserAlreadyExistsExceptionMapper implements ExceptionMapper<UserAlreadyExistsException> {
+  @Override
+  public Response toResponse(UserAlreadyExistsException exception) {
+    return Response.status(Status.CONFLICT).build();
+  }
+}