diff --git a/api-ref/source/_static b/api-ref/source/_static
new file mode 120000
index 00000000..af789d70
--- /dev/null
+++ b/api-ref/source/_static
@@ -0,0 +1 @@
+../../doc/source/_static
\ No newline at end of file
diff --git a/doc/requirements.txt b/doc/requirements.txt
index 2639062d..e1d3e7ec 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -1,4 +1,4 @@
-sphinx>=3.3.1 # BSD
+sphinx>=3.3.1,<5.0.0 # BSD
 openstackdocstheme>=2.2.6 # Apache-2.0
 sphinxcontrib-httpdomain>=1.7.0 # BSD
 sphinxcontrib-pecanwsme>=0.10.0 # Apache-2.0
diff --git a/tox.ini b/tox.ini
index 5965fcc5..36f0f977 100644
--- a/tox.ini
+++ b/tox.ini
@@ -66,6 +66,15 @@ commands = sphinx-build -W --keep-going -b html doc/source doc/build/html
 #   sphinx-build -W --keep-going -b latex doc/source doc/build/pdf
 #   make -C doc/build/pdf
 
+[testenv:api-ref]
+# This environment is called from CI scripts to test and publish
+# the API Ref to docs.openstack.org.
+deps = -r{toxinidir}/doc/requirements.txt
+allowlist_externals = rm
+commands =
+  rm -rf api-ref/build
+  sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
+
 [testenv:venv]
 commands = {posargs}