diff --git a/src/api2/admin/datastore.rs b/src/api2/admin/datastore.rs
index 9e9b2e23..9487bcf4 100644
--- a/src/api2/admin/datastore.rs
+++ b/src/api2/admin/datastore.rs
@@ -60,21 +60,34 @@ fn group_backups(backup_list: Vec<BackupInfo>) -> HashMap<String, Vec<BackupInfo
     group_hash
 }
 
+#[api(
+    input: {
+        properties: {
+            store: {
+                schema: DATASTORE_SCHEMA,
+            },
+        },
+    },
+    returns: {
+        type: Array,
+        description: "Returns the list of backup groups.",
+        items: {
+            type: GroupListItem,
+        }
+    },
+)]
+/// List backup groups.
 fn list_groups(
-    param: Value,
-    _info: &ApiMethod,
-    _rpcenv: &mut dyn RpcEnvironment,
-) -> Result<Value, Error> {
+    store: String,
+) -> Result<Vec<GroupListItem>, Error> {
 
-    let store = param["store"].as_str().unwrap();
-
-    let datastore = DataStore::lookup_datastore(store)?;
+    let datastore = DataStore::lookup_datastore(&store)?;
 
     let backup_list = BackupInfo::list_backups(&datastore.base_path())?;
 
     let group_hash = group_backups(backup_list);
 
-    let mut groups = vec![];
+    let mut groups = Vec::new();
 
     for (_group_id, mut list) in group_hash {
 
@@ -83,16 +96,17 @@ fn list_groups(
         let info = &list[0];
         let group = info.backup_dir.group();
 
-        groups.push(json!({
-            "backup-type": group.backup_type(),
-            "backup-id": group.backup_id(),
-            "last-backup": info.backup_dir.backup_time().timestamp(),
-            "backup-count": list.len() as u64,
-            "files": info.files,
-        }));
+        let result_item = GroupListItem {
+            backup_type: group.backup_type().to_string(),
+            backup_id: group.backup_id().to_string(),
+            last_backup: info.backup_dir.backup_time().timestamp(),
+            backup_count: list.len() as u64,
+            files: info.files.clone(),
+        };
+        groups.push(result_item);
     }
 
-    Ok(json!(groups))
+    Ok(groups)
 }
 
 fn list_snapshot_files (
@@ -652,15 +666,7 @@ const DATASTORE_INFO_SUBDIRS: SubdirMap = &[
     (
         "groups",
         &Router::new()
-            .get(
-                &ApiMethod::new(
-                    &ApiHandler::Sync(&list_groups),
-                    &ObjectSchema::new(
-                        "List backup groups.",
-                        &sorted!([ ("store", false, &DATASTORE_SCHEMA) ]),
-                    )
-                )
-            )
+            .get(&API_METHOD_LIST_GROUPS)
     ),
     (
         "prune",
diff --git a/src/api2/pull.rs b/src/api2/pull.rs
index 7028593a..072df5db 100644
--- a/src/api2/pull.rs
+++ b/src/api2/pull.rs
@@ -299,17 +299,12 @@ pub async fn pull_store(
 
     let mut result = client.get(&path, None).await?;
 
-    let list = result["data"].as_array_mut().unwrap();
+    let mut list: Vec<GroupListItem> = serde_json::from_value(result["data"].take())?;
 
     list.sort_unstable_by(|a, b| {
-        let a_id = a["backup-id"].as_str().unwrap();
-        let a_backup_type = a["backup-type"].as_str().unwrap();
-        let b_id = b["backup-id"].as_str().unwrap();
-        let b_backup_type = b["backup-type"].as_str().unwrap();
-
-        let type_order = a_backup_type.cmp(b_backup_type);
+        let type_order = a.backup_type.cmp(&b.backup_type);
         if type_order == std::cmp::Ordering::Equal {
-            a_id.cmp(b_id)
+            a.backup_id.cmp(&b.backup_id)
         } else {
             type_order
         }
@@ -318,13 +313,9 @@ pub async fn pull_store(
     let mut errors = false;
 
     for item in list {
-
-        let id = item["backup-id"].as_str().unwrap();
-        let btype = item["backup-type"].as_str().unwrap();
-
-        let group = BackupGroup::new(btype, id);
+        let group = BackupGroup::new(&item.backup_type, &item.backup_id);
         if let Err(err) = pull_group(worker, client, src_repo, tgt_store.clone(), &group).await {
-            worker.log(format!("sync group {}/{} failed - {}", btype, id, err));
+            worker.log(format!("sync group {}/{} failed - {}", item.backup_type, item.backup_id, err));
             errors = true;
             // continue
         }
diff --git a/src/api2/types.rs b/src/api2/types.rs
index 86decc7b..8a3d6ea4 100644
--- a/src/api2/types.rs
+++ b/src/api2/types.rs
@@ -192,6 +192,40 @@ pub const PROXMOX_USER_ID_SCHEMA: Schema = StringSchema::new("User ID")
 
 // Complex type definitions
 
+#[api(
+    properties: {
+        "backup-type": {
+            schema: BACKUP_TYPE_SCHEMA,
+        },
+        "backup-id": {
+            schema: BACKUP_ID_SCHEMA,
+        },
+        "last-backup": {
+            schema: BACKUP_TIME_SCHEMA,
+        },
+        "backup-count": {
+            type: Integer,
+        },
+        files: {
+            items: {
+                schema: BACKUP_ARCHIVE_NAME_SCHEMA
+            },
+        },
+    },
+)]
+#[derive(Serialize, Deserialize)]
+#[serde(rename_all="kebab-case")]
+/// Basic information about a backup group.
+pub struct GroupListItem {
+    pub backup_type: String, // enum
+    pub backup_id: String,
+    pub last_backup: i64,
+    /// Number of contained snapshots
+    pub backup_count: u64,
+    /// List of contained archive files.
+    pub files: Vec<String>,
+}
+
 #[api(
     properties: {
         "backup-type": {