diff --git a/pom.xml b/pom.xml
index 6991d94..5a5d8c5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
 
   <groupId>org.openconext</groupId>
   <artifactId>voot-service</artifactId>
-  <version>5.0.1</version>
+  <version>6.0.0-SNAPSHOT</version>
   <packaging>jar</packaging>
 
   <name>voot-service</name>
diff --git a/src/main/java/voot/ExternalGroupsService.java b/src/main/java/voot/ExternalGroupsService.java
index ed797d0..932e3ed 100644
--- a/src/main/java/voot/ExternalGroupsService.java
+++ b/src/main/java/voot/ExternalGroupsService.java
@@ -117,7 +117,8 @@ public Set<Group> getAllGroups() {
 
     protected Set<Group> filterDuplicatesWithLowerImportance(List<Group> groups) {
         return groups.stream().collect(groupingBy(group -> group.id)).values().stream()
-                .map(groupList -> groupList.stream().max(Comparator.comparing(group -> group.membership)).get()).collect(toSet());
+                .map(groupList -> groupList.stream().max(Comparator.comparing(group -> group.membership)).get())
+                .collect(toSet());
     }
 
     @SneakyThrows
diff --git a/src/main/java/voot/VootServiceApplication.java b/src/main/java/voot/VootServiceApplication.java
index 25e8875..99bff49 100644
--- a/src/main/java/voot/VootServiceApplication.java
+++ b/src/main/java/voot/VootServiceApplication.java
@@ -64,6 +64,8 @@ public ExternalGroupsService externalGroupsService(
                     return new OpenSocialMembersClient(configuration);
                 case GUESTS:
                     return new EduIDGuestProvider(configuration);
+                case INVITE:
+                    return new InviteProvider(configuration);
                 default:
                     throw new IllegalArgumentException("Unknown external provider-type: " + type);
             }
diff --git a/src/main/java/voot/model/User.java b/src/main/java/voot/model/User.java
index 8a51f07..d1e076d 100644
--- a/src/main/java/voot/model/User.java
+++ b/src/main/java/voot/model/User.java
@@ -8,9 +8,9 @@
 @Getter
 public class User {
 
-    private String clientId;
-    private String unspecifiedId;
-    private String schacHomeOrganization;
+    private final String clientId;
+    private final String unspecifiedId;
+    private final String schacHomeOrganization;
 
     public User(BearerTokenAuthentication bearerTokenAuthentication) {
         Map<String, Object> tokenAttributes = bearerTokenAuthentication.getTokenAttributes();
diff --git a/src/main/java/voot/provider/GroupProviderType.java b/src/main/java/voot/provider/GroupProviderType.java
index c0507ab..f89fc8d 100644
--- a/src/main/java/voot/provider/GroupProviderType.java
+++ b/src/main/java/voot/provider/GroupProviderType.java
@@ -2,6 +2,6 @@
 
 public enum GroupProviderType {
 
-    TEAMS, OPEN_SOCIAL, OPEN_SOCIAL_MEMBERS, VOOT2, GUESTS
+    TEAMS, OPEN_SOCIAL, OPEN_SOCIAL_MEMBERS, VOOT2, GUESTS, INVITE
 
 }
diff --git a/src/main/java/voot/provider/InviteProvider.java b/src/main/java/voot/provider/InviteProvider.java
new file mode 100644
index 0000000..0dd1dda
--- /dev/null
+++ b/src/main/java/voot/provider/InviteProvider.java
@@ -0,0 +1,63 @@
+package voot.provider;
+
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.RequestEntity;
+import org.springframework.http.ResponseEntity;
+import voot.model.Group;
+import voot.model.Member;
+import voot.model.Membership;
+
+import java.net.URI;
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class InviteProvider extends AbstractProvider {
+
+    private final String groupMembershipsUrlTemplate;
+
+    public InviteProvider(Configuration configuration) {
+        super(configuration);
+        groupMembershipsUrlTemplate = "%s/api/voot/%s";
+    }
+
+    @Override
+    public boolean shouldBeQueriedForMemberships(String schacHomeOrganization) {
+        return true;
+    }
+
+    @Override
+    public Set<Group> getGroupMemberships(String uid) {
+        String uri = String.format(groupMembershipsUrlTemplate, configuration.url, uid);
+        RequestEntity<List<Map<String, String>>> requestEntity = new RequestEntity<>(HttpMethod.GET, URI.create(uri));
+        return restTemplate.exchange(requestEntity, new ParameterizedTypeReference<List<Map<String, String>>>() {
+        }).getBody().stream()
+                .map(this::parseGroup)
+                .collect(Collectors.toSet());
+    }
+
+    private Group parseGroup(Map<String, String> map) {
+        String name = map.get("name");
+        return new Group(map.get("urn"), name, name, "Invite", Membership.MEMBER);
+    }
+
+    @Override
+    public Set<Group> getAllGroups() {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public Optional<Group> getGroupMembership(String uid, String groupId) {
+        return Optional.empty();
+    }
+
+    @Override
+    public Set<Member> getMembers(String groupId) {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public Set<Member> getMembers(String personId, String groupId) {
+        return Collections.emptySet();
+    }
+}
diff --git a/src/test/java/voot/VootServiceApplicationTest.java b/src/test/java/voot/VootServiceApplicationTest.java
index 6a52967..4b2e1f9 100644
--- a/src/test/java/voot/VootServiceApplicationTest.java
+++ b/src/test/java/voot/VootServiceApplicationTest.java
@@ -23,12 +23,12 @@ void externalGroupsService() throws IOException {
         ExternalGroupsService externalGroupsService =
                 app.externalGroupsService(new ClassPathResource("/testAllExternalProviders.yml"));
         Object providers = ReflectionTestUtils.getField(externalGroupsService, "providers");
-        assertEquals(5, ((List) providers).size());
+        assertEquals(6, ((List) providers).size());
     }
 
 
     @Test
-    void externalGroupsServiceUnknown() throws IOException {
+    void externalGroupsServiceUnknown() {
         VootServiceApplication app = new VootServiceApplication();
         Assertions.assertThrows(IllegalArgumentException.class,
                 () -> app.externalGroupsService(new ClassPathResource("/testUnknownExternalProviders.yml")));
diff --git a/src/test/java/voot/provider/InviteProviderTest.java b/src/test/java/voot/provider/InviteProviderTest.java
new file mode 100644
index 0000000..b70f9a4
--- /dev/null
+++ b/src/test/java/voot/provider/InviteProviderTest.java
@@ -0,0 +1,57 @@
+package voot.provider;
+
+import com.nimbusds.jose.util.IOUtils;
+import org.junit.jupiter.api.Test;
+import org.springframework.core.io.ClassPathResource;
+import voot.AbstractTest;
+import voot.model.Group;
+
+import java.io.IOException;
+import java.util.Set;
+
+import static com.github.tomakehurst.wiremock.client.WireMock.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+
+class InviteProviderTest extends AbstractTest {
+
+    private final InviteProvider subject = new InviteProvider(
+            new Provider.Configuration(GroupProviderType.INVITE, "http://localhost:8889",
+                    new Provider.Configuration.Credentials("user", "password"),
+                    2000, "N/A", "invite"));
+
+    @Test
+    void getGroupMemberships() throws IOException {
+        String json = IOUtils.readInputStreamToString(new ClassPathResource("json/invite/group_memberships.json").getInputStream());
+        String urn = "urn:collab:person:example.com:admin";
+        stubFor(get(urlPathEqualTo("/api/voot/" + urn))
+                .willReturn(aResponse()
+                        .withStatus(200)
+                        .withHeader("Content-type", "application/json").
+                        withBody(json)));
+        Set<Group> groupMemberships = subject.getGroupMemberships(urn);
+        assertEquals(2, groupMemberships.size());
+    }
+
+    @Test
+    void getAllGroups() {
+        assertEquals(0, subject.getAllGroups().size());
+    }
+
+    @Test
+    void getGroupMembership() {
+        assertFalse(subject.getGroupMembership("uid", "groupId").isPresent());
+
+    }
+
+    @Test
+    void getMembers() {
+        assertEquals(0, subject.getMembers("groupId").size());
+    }
+
+    @Test
+    void getMembersByPersonId() {
+        assertEquals(0, subject.getMembers("personId", "groupId").size());
+    }
+}
diff --git a/src/test/resources/json/invite/group_memberships.json b/src/test/resources/json/invite/group_memberships.json
new file mode 100644
index 0000000..4e73e06
--- /dev/null
+++ b/src/test/resources/json/invite/group_memberships.json
@@ -0,0 +1,10 @@
+[
+  {
+    "urn": "urn1",
+    "name": "administrator"
+  },
+  {
+    "urn": "urn2",
+    "name": "guest"
+  }
+]
diff --git a/src/test/resources/testAllExternalProviders.yml b/src/test/resources/testAllExternalProviders.yml
index 35d816b..9f42928 100644
--- a/src/test/resources/testAllExternalProviders.yml
+++ b/src/test/resources/testAllExternalProviders.yml
@@ -54,3 +54,14 @@ externalGroupProviders:
     name: "Bar",
     timeoutMillis: 5000
   }
+  - {
+    type: "invite",
+    url: "http://localhost:8999/",
+    credentials: {
+      username: "foo",
+      secret: "bar"
+    },
+    schacHomeOrganization: "N/A",
+    name: "Invite",
+    timeoutMillis: 5000
+  }