diff --git a/.gitignore b/.gitignore
index b8df0fecc6d9a00ab193d72837c0f2900cf241d7..0c572cedf6a9d04b282f94fb3e5a9f9109265311 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@
 .pytest/
 .python-version
 .ipynb_checkpoints/
+.python-version
 __pycache__
 .mypy_cache
 *.pyc
diff --git a/.python-version b/.python-version
deleted file mode 100644
index bec3a35ee8b46e4d58c0439c3efd9ab2dacd0cfd..0000000000000000000000000000000000000000
--- a/.python-version
+++ /dev/null
@@ -1 +0,0 @@
-system
diff --git a/nomad/app/optimade/index.py b/nomad/app/optimade/index.py
index 4cb95f691965672405e2eeb5d3ad91291ca852c4..19febfbc7a41b45c9e9406af0a4e36a5748060bf 100644
--- a/nomad/app/optimade/index.py
+++ b/nomad/app/optimade/index.py
@@ -18,7 +18,7 @@ from flask import request
 from .api import api, url, base_request_args
 from .models import json_api_single_response_model, base_endpoint_parser, json_api_single_response_model, Meta, json_api_list_response_model
 
-ns = api.namespace('', description='This is the OPTiMaDe index for NOMAD\' implementations.')
+ns = api.namespace('index/v0', description='This is the OPTiMaDe index for NOMAD\' implementations.')
 
 
 @ns.route('/info')
diff --git a/tests/app/test_optimade.py b/tests/app/test_optimade.py
index c5ecd0a5f3f60073c71179e4d016ef4bb74dad74..26c91689401f0459fa2d09bc55b5b41907bdd9ca 100644
--- a/tests/app/test_optimade.py
+++ b/tests/app/test_optimade.py
@@ -31,7 +31,7 @@ def api(session_client):
 
 @pytest.fixture(scope='session')
 def index_api(session_client):
-    return BlueprintClient(session_client, '/optimade')
+    return BlueprintClient(session_client, '/optimade/index/v0')
 
 
 def test_index(index_api):