diff --git a/swh/search/api/server.py b/swh/search/api/server.py
--- a/swh/search/api/server.py
+++ b/swh/search/api/server.py
@@ -16,6 +16,8 @@
 from .. import get_search
 from ..interface import SearchInterface
 
+logger = logging.getLogger(__name__)
+
 
 def _get_search():
     global search
@@ -41,6 +43,13 @@
     return "SWH Search API server"
 
 
+@app.before_first_request
+def initialized_index():
+    search = _get_search()
+    logger.info("Initializing indexes with configuration: ", search.origin_config)
+    search.initialize()
+
+
 api_cfg = None
 
 
diff --git a/swh/search/tests/test_server.py b/swh/search/tests/test_server.py
--- a/swh/search/tests/test_server.py
+++ b/swh/search/tests/test_server.py
@@ -11,9 +11,15 @@
 
 from swh.core.api import RPCServerApp
 from swh.core.config import load_from_envvar
+from swh.search.api import server
 from swh.search.api.server import load_and_check_config, make_app_from_configfile
 
 
+def teardown_function():
+    # Ensure there is no configuration loaded from a previous test
+    server.api_cfg = None
+
+
 def _write_config_file(tmp_path, monkeypatch, content):
     conf_path = os.path.join(str(tmp_path), "search.yml")
     with open(conf_path, "w") as f:
@@ -32,8 +38,10 @@
     swh_search_server_config_without_indexes,
 ) -> Dict[str, Any]:
     return {
-        **swh_search_server_config_without_indexes,
-        **{"indexes": {"origin": {"index": "test"}}},
+        "search": {
+            **{"indexes": {"origin": {"index": "test"}}},
+            **swh_search_server_config_without_indexes["search"],
+        }
     }
 
 
@@ -122,10 +130,27 @@
 def test_server_make_app_from_config_file_with_indexes(swh_search_config_with_indexes,):
     app = make_app_from_configfile()
     expected_cfg = load_from_envvar()
-
     assert app is not None
     assert isinstance(app, RPCServerApp)
     assert app.config["search"] == expected_cfg["search"]
 
     app2 = make_app_from_configfile()
     assert app is app2
+
+
+def test_server_first_call_initialize_elasticsearch(
+    swh_search_config_with_indexes, mocker
+):
+    """Test the initialize method is called during the first and first only
+       request to the server"""
+    mock = mocker.patch("swh.search.elasticsearch.ElasticSearch.initialize")
+
+    app = make_app_from_configfile()
+    app.config["TESTING"] = True
+    tc = app.test_client()
+
+    tc.get("/")
+    assert mock.call_count == 1
+
+    tc.get("/")
+    assert mock.call_count == 1