diff --git a/tox.ini b/tox.ini
index 381d8037..70fbc905 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,37 +1,75 @@
 [tox]
 envlist=black,flake8,mypy,py3
 
 [testenv]
 extras =
   testing
 deps =
   pytest-cov
 commands =
   pytest \
     slow:  --hypothesis-profile=swh-web \
     !slow: --hypothesis-profile=swh-web-fast \
       --cov {envsitepackagesdir}/swh/web --cov-branch {posargs} {envsitepackagesdir}/swh/web
 
 [testenv:flake8]
 skip_install = true
 deps =
   flake8
 commands =
   {envpython} -m flake8 \
     --exclude=.tox,.git,__pycache__,.eggs,*.egg,node_modules
 
 [testenv:mypy]
 setenv = DJANGO_SETTINGS_MODULE = swh.web.settings.development
 extras =
   testing
 deps =
   mypy
 commands =
   mypy swh
 
 [testenv:black]
 skip_install = true
 deps =
   black==19.10b0
 commands =
   {envpython} -m black --exclude swh/web/tests/resources --check swh
+
+# build documentation outside swh-environment using the current
+# git HEAD of swh-docs, is executed on CI for each diff to prevent
+# breaking doc build
+[testenv:sphinx]
+whitelist_externals = make
+usedevelop = true
+extras =
+  testing
+deps =
+  # fetch and install swh-docs in develop mode
+  -e git+https://forge.softwareheritage.org/source/swh-docs#egg=swh.docs
+
+setenv =
+  SWH_PACKAGE_DOC_TOX_BUILD = 1
+  # turn warnings into errors
+  SPHINXOPTS = -W
+commands =
+  make -I ../.tox/sphinx/src/swh-docs/swh/ -C docs
+
+
+# build documentation only inside swh-environment using local state
+# of swh-docs package
+[testenv:sphinx-dev]
+whitelist_externals = make
+usedevelop = true
+extras =
+  testing
+deps =
+  # install swh-docs in develop mode
+  -e ../swh-docs
+
+setenv =
+  SWH_PACKAGE_DOC_TOX_BUILD = 1
+  # turn warnings into errors
+  SPHINXOPTS = -W
+commands =
+  make -I ../.tox/sphinx-dev/src/swh-docs/swh/ -C docs