diff --git a/docs/Makefile b/docs/Makefile
index 8e5394ff..0170576d 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -7,11 +7,6 @@ SPHINXBUILD   = sphinx-build
 SOURCEDIR     = .
 BUILDDIR      = _build
 
-# sphinx-hoverxref expected variables
-export READTHEDOCS=True
-export READTHEDOCS_PROJECT=sphinx-hoverxref
-export READTHEDOCS_VERSION=latest
-
 # Put it first so that "make" without argument is like "make help".
 help:
 	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
diff --git a/docs/conf.py b/docs/conf.py
index 914ae2e7..8294ece9 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-#
 # Configuration file for the Sphinx documentation builder.
 #
 # This file does only contain a selection of the most common options. For a
@@ -75,12 +73,8 @@
     'sphinx': 'tooltip',
 }
 
-# Used when building the documentation from the terminal and using a local Read
-# the Docs instance as backend
-hoverxref_api_host = 'http://localhost:8000'
-
-if os.environ.get('READTHEDOCS') == 'True':
-    # Building on Read the Docs
+# Used when building the documentation locally.
+if os.environ.get('READTHEDOCS') != 'True':
     hoverxref_api_host = 'https://readthedocs.org'
 
     if os.environ.get('PROXIED_API_ENDPOINT') == 'True':
diff --git a/docs/configuration.rst b/docs/configuration.rst
index 79771263..d99c2a59 100644
--- a/docs/configuration.rst
+++ b/docs/configuration.rst
@@ -151,14 +151,14 @@ These settings are global and have effect on both, tooltips and modal dialogues.
 
 .. confval:: hoverxref_api_host
 
-   Description: Host URL for the API to retrieve the content of the floating window
+   Description: Host or root URL for the API to retrieve the content of the floating window
 
    .. warning::
 
      You shouldn't modify this setting unless you know what you are doing.
      Its default should be fine to build the documentation and make it work in Read the Docs.
 
-   Default: ``https://readthedocs.org``
+   Default: ``/_``
 
    Type: string
 
diff --git a/docs/development.rst b/docs/development.rst
index 4e43ba8c..747613a3 100644
--- a/docs/development.rst
+++ b/docs/development.rst
@@ -54,24 +54,6 @@ Serve the documentation locally with this command:
 
 Now, you can hit http://localhost:9000/ and you should see your documentation here.
 
-
-Avoid CORS on local backend
-+++++++++++++++++++++++++++
-
-When building the documentation locally,
-the API calls will be blocked by the browser because of :abbr:`CORS (Cross Origin Resource Sharing)`
-(you are hitting the URL http://localhost:9000/ and the API calls are to https://readthedocs.org/).
-
-You can disable this while developing our extension.
-To do this, you can open Google Chrome with these arguments:
-
-.. prompt:: bash
-
-   google-chrome-stable --disable-web-security --user-data-dir='/tmp/testing'
-
-If Firefox, you can install this add-ons: `Allow CORS: Access-Control-Allow-Origin <https://addons.mozilla.org/es/firefox/addon/access-control-allow-origin/>`_.
-
-
 Using a local Read the Docs instance
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/hoverxref/extension.py b/hoverxref/extension.py
index f8f3ce4c..78d22169 100644
--- a/hoverxref/extension.py
+++ b/hoverxref/extension.py
@@ -348,13 +348,13 @@ def setup(app):
     app.add_config_value('hoverxref_default_type', 'tooltip', 'env')
     app.add_config_value('hoverxref_intersphinx', [], 'env')
     app.add_config_value('hoverxref_intersphinx_types', {}, 'env')
-    app.add_config_value('hoverxref_api_host', 'https://readthedocs.org', 'env')
+    app.add_config_value('hoverxref_api_host', '/_', 'env')
     app.add_config_value('hoverxref_sphinx_version', sphinx.__version__, 'env')
     app.add_config_value('hoverxref_tooltip_lazy', False, 'env')
 
     # Tooltipster settings
     # Deprecated in favor of ``hoverxref_api_host``
-    app.add_config_value('hoverxref_tooltip_api_host', 'https://readthedocs.org', 'env')
+    app.add_config_value('hoverxref_tooltip_api_host', '/_', 'env')
     app.add_config_value('hoverxref_tooltip_theme', ['tooltipster-shadow', 'tooltipster-shadow-custom'], 'env')
     app.add_config_value('hoverxref_tooltip_interactive', True, 'env')
     app.add_config_value('hoverxref_tooltip_maxwidth', 450, 'env')
diff --git a/tests/test_htmltag.py b/tests/test_htmltag.py
index ebf38cd1..45c85abc 100644
--- a/tests/test_htmltag.py
+++ b/tests/test_htmltag.py
@@ -44,7 +44,7 @@ def test_js_render(app, status, warning):
         "animationDuration: 0",
         "contentAsHTML: true",
         "content: 'Loading...'",
-        "var url = 'https://readthedocs.org' + '/api/v3/embed/?' + $.param(params);",
+        "var url = '/_' + '/api/v3/embed/?' + $.param(params);",
         textwrap.indent(
             textwrap.dedent("""
             var params = {{