diff --git a/src/api/groups.rs b/src/api/groups.rs
index 72f4791..ebfb6d7 100644
--- a/src/api/groups.rs
+++ b/src/api/groups.rs
@@ -5,9 +5,23 @@ use serde::{Deserialize, Serialize};
 use schemars::JsonSchema;
 
 use crate::api::{
-    BulkCreateDomainExtension, BulkDeleteDomainExtension, BulkReadDomainExtension,
-    BulkUpdateDomainExtension, DomainExtension, DomainType
+    DomainObject, DomainType
 };
+use crate::{ApiClient, Client, Result};
+
+impl Client {
+    pub fn host_group_api(&self) -> ApiClient<HostGroup> {
+        self.into()
+    }
+
+    pub fn service_group_api(&self) -> ApiClient<ServiceGroup> {
+        self.into()
+    }
+
+    pub fn contact_group_api(&self) -> ApiClient<ContactGroup> {
+        self.into()
+    }
+}
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[cfg_attr(feature = "schemars", derive(JsonSchema))]
@@ -22,33 +36,12 @@ impl Group {
     }
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[cfg_attr(feature = "schemars", derive(JsonSchema))]
-pub struct GroupAlias {
-    alias: String
-}
-
-impl GroupAlias {
-    pub fn new(alias: String) -> Self {
-        Self { alias }
+impl From<DomainObject<serde_json::Value>> for Group {
+    fn from(value: DomainObject<serde_json::Value>) -> Self {
+        Self::new(value.id, value.title.unwrap_or_default())
     }
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[cfg_attr(feature = "schemars", derive(JsonSchema))]
-pub struct BulkGroupUpdate {
-    name: String,
-    attributes: GroupAlias
-}
-
-impl BulkGroupUpdate {
-    pub fn new(name: String, alias: String) -> Self {
-        Self {
-            name,
-            attributes: GroupAlias::new(alias)
-        }
-    }
-}
 
 macro_rules! domain_group {
     ($id:ident, $typ:expr) => {
@@ -70,25 +63,80 @@ macro_rules! domain_group {
             }
         }
 
-        impl DomainExtension for $id {
-            const DOMAIN_TYPE: DomainType = $typ;
-
-            type CreationRequest = Group;
-            type CreationQuery = ();
-            type ReadQuery = ();
-            type UpdateRequest = GroupAlias;
-            type DeleteQuery = ();
+        impl From<DomainObject<serde_json::Value>> for $id {
+            fn from(value: DomainObject<serde_json::Value>) -> Self {
+                Self(Group::from(value))
+            }
         }
 
-        impl BulkCreateDomainExtension for $id {}
-        impl BulkReadDomainExtension for $id {
-            type BulkReadQuery = ();
+        impl From<&Client> for ApiClient<$id> {
+            fn from(value: &Client) -> Self {
+                Self::new(value)
+            }
         }
-        impl BulkUpdateDomainExtension for $id {
-            type BulkUpdateRequest = BulkGroupUpdate;
-        }
-        impl BulkDeleteDomainExtension for $id {}
 
+        impl ApiClient<$id> {
+            pub async fn create(&self, group: &$id) -> Result<()> {
+                self.inner.create($typ, group, &()).await
+            }
+            pub async fn read(&self, id: &str) -> Result<$id> {
+                let obj: DomainObject<serde_json::Value> =
+                    self.inner.read($typ, id, &()).await?;
+                Ok($id::from(obj))
+            }
+            pub async fn update(&self, id: &str, alias: &str) -> Result<()> {
+                #[derive(Serialize)]
+                struct Body<'a> {
+                    alias: &'a str
+                }
+
+                self.inner.update($typ, id, &Body { alias }).await
+            }
+            pub async fn delete(&self, id: &str) -> Result<()> {
+                self.inner.delete($typ, id, &()).await
+            }
+
+            pub async fn bulk_create(&self, entries: &[$id]) -> Result<()> {
+                self.inner.bulk_create($typ, entries, &()).await
+            }
+            pub async fn bulk_read(&self) -> Result<Vec<$id>> {
+                let entries: Vec<DomainObject<serde_json::Value>> =
+                    self.inner.bulk_read($typ, &()).await?;
+                let objects = entries.into_iter()
+                    .map($id::from)
+                    .collect();
+                Ok(objects)
+            }
+            pub async fn bulk_update(&self, entries: &[Group]) -> Result<()> {
+                #[derive(Serialize)]
+                struct UpdateAttributes<'a> {
+                    alias: &'a str
+                }
+                #[derive(Serialize)]
+                struct UpdateRequest<'a> {
+                    name: &'a str,
+                    attributes: UpdateAttributes<'a>
+                }
+                impl <'a> UpdateRequest<'a> {
+                    fn from(value: &'a Group) -> Self {
+                        Self {
+                            name: value.name.as_str(),
+                            attributes: UpdateAttributes {
+                                alias: value.alias.as_str()
+                            }
+                        }
+                    }
+                }
+
+                let entries = entries.iter()
+                    .map(UpdateRequest::from)
+                    .collect::<Vec<_>>();
+                self.inner.bulk_update($typ, &entries).await
+            }
+            pub async fn bulk_delete(&self, entries: &[String]) -> Result<()> {
+                self.inner.bulk_delete($typ, entries).await
+            }
+        }
     }
 }
 
diff --git a/src/main.rs b/src/main.rs
index cf60bbe..22afebb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,9 +8,13 @@ const PASSWORD: &str = "C5t71DUPAu2D";
 
 #[tokio::main]
 async fn main() -> Result<()> {
+    let log_config = simplelog::ConfigBuilder::new()
+        .set_location_level(simplelog::LevelFilter::Error)
+        .build();
+
     simplelog::TermLogger::init(
         simplelog::LevelFilter::Trace,
-        simplelog::Config::default(),
+        log_config,
         simplelog::TerminalMode::Stderr,
         simplelog::ColorChoice::Auto,
     )
@@ -26,6 +30,9 @@ async fn main() -> Result<()> {
     test_folders(client.clone()).await?;
     test_hosts(client.clone()).await?;
     test_hosttags(client.clone()).await?;
+    test_host_groups(client.clone()).await?;
+    test_service_groups(client.clone()).await?;
+    test_contact_groups(client.clone()).await?;
 
     info!("tests done; all pass");
     Ok(())
@@ -194,3 +201,186 @@ async fn test_hosttags(client: Client) -> Result<()> {
 
     Ok(())
 }
+
+async fn test_host_groups(client: Client) -> Result<()> {
+    use checkmk_api::api::groups::*;
+    const TESTGROUP: &str = "test-host-group";
+    info!("testing host groups");
+
+    let api = client.host_group_api();
+
+    info!("creating test host group");
+    api.create(&HostGroup::new(TESTGROUP.to_string(), "Test Host Group".to_string()))
+        .await
+        .inspect_err(|e| error!("failed to create host group: {e}"))?;
+
+    let group = api
+        .read(TESTGROUP)
+        .await
+        .inspect_err(|e| error!("failed to read host group: {e}"))?;
+    info!("host group config: {group:#?}");
+
+    info!("updating host group");
+    api.update(TESTGROUP, "Updated Test Host Group")
+        .await
+        .inspect_err(|e| error!("failed to update host group: {e}"))?;
+
+    info!("bulk creating additional host groups");
+    api.bulk_create(&[
+        HostGroup::new("test-host-group-2".to_string(), "Test Host Group 2".to_string()),
+        HostGroup::new("test-host-group-3".to_string(), "Test Host Group 3".to_string()),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk create host groups: {e}"))?;
+
+    let groups = api
+        .bulk_read()
+        .await
+        .inspect_err(|e| error!("failed to bulk read host groups: {e}"));
+    info!("all host groups: {groups:?}");
+
+    info!("bulk updating host groups");
+    api.bulk_update(&[
+        Group::new("test-host-group-2".to_string(), "Updated Host Group 2".to_string()),
+        Group::new("test-host-group-3".to_string(), "Updated Host Group 3".to_string()),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk update host groups: {e}"))?;
+
+    info!("bulk deleting extra host groups");
+    api.bulk_delete(&[
+        "test-host-group-2".to_string(),
+        "test-host-group-3".to_string(),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk delete host groups: {e}"))?;
+
+    info!("deleting test host group");
+    api.delete(TESTGROUP)
+        .await
+        .inspect_err(|e| error!("failed to delete host group: {e}"))?;
+
+    Ok(())
+}
+
+async fn test_service_groups(client: Client) -> Result<()> {
+    use checkmk_api::api::groups::*;
+    const TESTGROUP: &str = "test-service-group";
+    info!("testing service groups");
+
+    let api = client.service_group_api();
+
+    info!("creating test service group");
+    api.create(&ServiceGroup::new(TESTGROUP.to_string(), "Test Service Group".to_string()))
+        .await
+        .inspect_err(|e| error!("failed to create service group: {e}"))?;
+
+    let group = api
+        .read(TESTGROUP)
+        .await
+        .inspect_err(|e| error!("failed to read service group: {e}"))?;
+    info!("service group config: {group:#?}");
+
+    info!("updating service group");
+    api.update(TESTGROUP, "Updated Test Service Group")
+        .await
+        .inspect_err(|e| error!("failed to update service group: {e}"))?;
+
+    info!("bulk creating additional service groups");
+    api.bulk_create(&[
+        ServiceGroup::new("test-service-group-2".to_string(), "Test Service Group 2".to_string()),
+        ServiceGroup::new("test-service-group-3".to_string(), "Test Service Group 3".to_string()),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk create service groups: {e}"))?;
+
+    let groups = api
+        .bulk_read()
+        .await
+        .inspect_err(|e| error!("failed to bulk read service groups: {e}"));
+    info!("all service groups: {groups:?}");
+
+    info!("bulk updating service groups");
+    api.bulk_update(&[
+        Group::new("test-service-group-2".to_string(), "Updated Service Group 2".to_string()),
+        Group::new("test-service-group-3".to_string(), "Updated Service Group 3".to_string()),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk update service groups: {e}"))?;
+
+    info!("bulk deleting extra service groups");
+    api.bulk_delete(&[
+        "test-service-group-2".to_string(),
+        "test-service-group-3".to_string(),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk delete service groups: {e}"))?;
+
+    info!("deleting test service group");
+    api.delete(TESTGROUP)
+        .await
+        .inspect_err(|e| error!("failed to delete service group: {e}"))?;
+
+    Ok(())
+}
+
+async fn test_contact_groups(client: Client) -> Result<()> {
+    use checkmk_api::api::groups::*;
+    const TESTGROUP: &str = "test-contact-group";
+    info!("testing contact groups");
+
+    let api = client.contact_group_api();
+
+    info!("creating test contact group");
+    api.create(&ContactGroup::new(TESTGROUP.to_string(), "Test Contact Group".to_string()))
+        .await
+        .inspect_err(|e| error!("failed to create contact group: {e}"))?;
+
+    let group = api
+        .read(TESTGROUP)
+        .await
+        .inspect_err(|e| error!("failed to read contact group: {e}"))?;
+    info!("contact group config: {group:#?}");
+
+    info!("updating contact group");
+    api.update(TESTGROUP, "Updated Test Contact Group")
+        .await
+        .inspect_err(|e| error!("failed to update contact group: {e}"))?;
+
+    info!("bulk creating additional contact groups");
+    api.bulk_create(&[
+        ContactGroup::new("test-contact-group-2".to_string(), "Test Contact Group 2".to_string()),
+        ContactGroup::new("test-contact-group-3".to_string(), "Test Contact Group 3".to_string()),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk create contact groups: {e}"))?;
+
+    let groups = api
+        .bulk_read()
+        .await
+        .inspect_err(|e| error!("failed to bulk read contact groups: {e}"));
+    info!("all contact groups: {groups:?}");
+
+    info!("bulk updating contact groups");
+    api.bulk_update(&[
+        Group::new("test-contact-group-2".to_string(), "Updated Contact Group 2".to_string()),
+        Group::new("test-contact-group-3".to_string(), "Updated Contact Group 3".to_string()),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk update contact groups: {e}"))?;
+
+    info!("bulk deleting extra contact groups");
+    api.bulk_delete(&[
+        "test-contact-group-2".to_string(),
+        "test-contact-group-3".to_string(),
+    ])
+    .await
+    .inspect_err(|e| error!("failed to bulk delete contact groups: {e}"))?;
+
+    info!("deleting test contact group");
+    api.delete(TESTGROUP)
+        .await
+        .inspect_err(|e| error!("failed to delete contact group: {e}"))?;
+
+    Ok(())
+}