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
@@ -14,6 +14,7 @@
 from swh.search.metrics import timed
 
 from .. import get_search
+from ..exc import SearchException
 from ..interface import SearchInterface
 
 logger = logging.getLogger(__name__)
@@ -32,6 +33,11 @@
 search = None
 
 
+@app.errorhandler(SearchException)
+def search_error_handler(exception):
+    return error_handler(exception, encode_data, status_code=400)
+
+
 @app.errorhandler(Exception)
 def my_error_handler(exception):
     return error_handler(exception, encode_data)
diff --git a/swh/search/tests/test_elasticsearch.py b/swh/search/tests/test_elasticsearch.py
--- a/swh/search/tests/test_elasticsearch.py
+++ b/swh/search/tests/test_elasticsearch.py
@@ -85,6 +85,13 @@
             "http://foobar.3.com",
         }
 
+    def test_search_ql_syntax_error(self):
+        self.search.origin_update(ORIGINS)
+        self.search.flush()
+
+        with pytest.raises(SearchQuerySyntaxError):
+            self.search.origin_search(query='origin : "foobar')
+
     def test_search_ql_datetimes(self):
         self.search.origin_update(ORIGINS)
         self.search.flush()