diff --git a/.flake8 b/.flake8
new file mode 100644
index 00000000..f81cf2c7
--- /dev/null
+++ b/.flake8
@@ -0,0 +1,3 @@
+[flake8]
+max-line-length = 79
+extend-ignore = E203, E501
diff --git a/.readthedocs.yml b/.readthedocs.yml
new file mode 100644
index 00000000..511ae165
--- /dev/null
+++ b/.readthedocs.yml
@@ -0,0 +1,11 @@
+---
+version: 2
+python:
+  # Keep version in sync with tox.ini (docs and gh-actions).
+  version: 3.7
+
+  install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs
diff --git a/docs/conf.py b/docs/conf.py
index 28f665cf..c7574bdf 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,41 +1,46 @@
 # -*- coding: utf-8 -*-
-#
-# PyJWT documentation build configuration file, created by
-# sphinx-quickstart on Thu Oct 22 18:11:10 2015.
-#
-# This file is execfile()d with the current directory set to its
-# containing dir.
-#
-# Note that not all possible configuration values are present in this
-# autogenerated file.
-#
-# All configuration values have a default; values that are commented out
-# serve to show the default.
-
+import codecs
 import os
 import re
-import shlex
-import sys
 
-# The theme to use for HTML and HTML Help pages.  See the documentation for
-# a list of builtin themes.
 import sphinx_rtd_theme
 
 
-# If extensions (or modules to document with autodoc) are in another directory,
-# add these directories to sys.path here. If the directory is relative to the
-# documentation root, use os.path.abspath to make it absolute, like shown here.
-# sys.path.insert(0, os.path.abspath('.'))
+def read(*parts):
+    """
+    Build an absolute path from *parts* and and return the contents of the
+    resulting file.  Assume UTF-8 encoding.
+    """
+    here = os.path.abspath(os.path.dirname(__file__))
+    with codecs.open(os.path.join(here, *parts), "rb", "utf-8") as f:
+        return f.read()
 
-# -- General configuration ------------------------------------------------
 
-# If your documentation needs a minimal Sphinx version, state it here.
-# needs_sphinx = '1.0'
+def find_version(*file_paths):
+    """
+    Build a path from *file_paths* and search for a ``__version__``
+    string inside.
+    """
+    version_file = read(*file_paths)
+    version_match = re.search(
+        r"^__version__ = ['\"]([^'\"]*)['\"]", version_file, re.M
+    )
+    if version_match:
+        return version_match.group(1)
+    raise RuntimeError("Unable to find version string.")
+
+
+# -- General configuration ------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = []
+extensions = [
+    "sphinx.ext.autodoc",
+    "sphinx.ext.doctest",
+    "sphinx.ext.intersphinx",
+    "sphinx.ext.todo",
+]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ["_templates"]
@@ -45,9 +50,6 @@
 # source_suffix = ['.rst', '.md']
 source_suffix = ".rst"
 
-# The encoding of source files.
-# source_encoding = 'utf-8-sig'
-
 # The master toctree document.
 master_doc = "index"
 
@@ -60,19 +62,11 @@
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
-# The short X.Y version.
-def get_version(package):
-    """
-    Return package version as listed in `__version__` in `init.py`.
-    """
-    with open(os.path.join("..", package, "__init__.py"), "rb") as init_py:
-        src = init_py.read().decode("utf-8")
-        return re.search("__version__ = ['\"]([^'\"]+)['\"]", src).group(1)
-
-
-version = get_version("jwt")
 # The full version, including alpha/beta/rc tags.
-release = version
+release = find_version("../src/jwt/__init__.py")
+
+# The short X.Y version.
+version = release.rsplit(u".", 1)[0]
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -81,40 +75,13 @@ def get_version(package):
 # Usually you set "language" from the command line for these cases.
 language = None
 
-# There are two options for replacing |today|: either, you set today to some
-# non-false value, then it is used:
-# today = ''
-# Else, today_fmt is used as the format for a strftime call.
-# today_fmt = '%B %d, %Y'
-
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 exclude_patterns = ["_build"]
 
-# The reST default role (used for this markup: `text`) to use for all
-# documents.
-# default_role = None
-
-# If true, '()' will be appended to :func: etc. cross-reference text.
-# add_function_parentheses = True
-
-# If true, the current module name will be prepended to all description
-# unit titles (such as .. function::).
-# add_module_names = True
-
-# If true, sectionauthor and moduleauthor directives will be shown in the
-# output. They are ignored by default.
-# show_authors = False
-
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = "sphinx"
 
-# A list of ignored prefixes for module index sorting.
-# modindex_common_prefix = []
-
-# If true, keep warnings as "system message" paragraphs in the built documents.
-# keep_warnings = False
-
 # If true, `todo` and `todoList` produce output, else they produce nothing.
 todo_include_todos = False
 
@@ -126,30 +93,6 @@ def get_version(package):
 
 html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
-# Theme options are theme-specific and customize the look and feel of a theme
-# further.  For a list of options available for each theme, see the
-# documentation.
-# html_theme_options = {}
-
-# Add any paths that contain custom themes here, relative to this directory.
-# html_theme_path = []
-
-# The name for this set of Sphinx documents.  If None, it defaults to
-# "<project> v<release> documentation".
-# html_title = None
-
-# A shorter title for the navigation bar.  Default is the same as html_title.
-# html_short_title = None
-
-# The name of an image file (relative to this directory) to place at the top
-# of the sidebar.
-# html_logo = None
-
-# The name of an image file (within the static path) to use as favicon of the
-# docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
-# pixels large.
-# html_favicon = None
-
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
@@ -162,115 +105,9 @@ def get_version(package):
     ]
 }
 
-# Add any extra paths that contain custom files (such as robots.txt or
-# .htaccess) here, relative to this directory. These files are copied
-# directly to the root of the documentation.
-# html_extra_path = []
-
-# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
-# using the given strftime format.
-# html_last_updated_fmt = '%b %d, %Y'
-
-# If true, SmartyPants will be used to convert quotes and dashes to
-# typographically correct entities.
-# html_use_smartypants = True
-
-# Custom sidebar templates, maps document names to template names.
-# html_sidebars = {}
-
-# Additional templates that should be rendered to pages, maps page names to
-# template names.
-# html_additional_pages = {}
-
-# If false, no module index is generated.
-# html_domain_indices = True
-
-# If false, no index is generated.
-# html_use_index = True
-
-# If true, the index is split into individual pages for each letter.
-# html_split_index = False
-
-# If true, links to the reST sources are added to the pages.
-# html_show_sourcelink = True
-
-# If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
-# html_show_sphinx = True
-
-# If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
-# html_show_copyright = True
-
-# If true, an OpenSearch description file will be output, and all pages will
-# contain a <link> tag referring to it.  The value of this option must be the
-# base URL from which the finished HTML is served.
-# html_use_opensearch = ''
-
-# This is the file name suffix for HTML files (e.g. ".xhtml").
-# html_file_suffix = None
-
-# Language to be used for generating the HTML full-text search index.
-# Sphinx supports the following languages:
-#   'da', 'de', 'en', 'es', 'fi', 'fr', 'hu', 'it', 'ja'
-#   'nl', 'no', 'pt', 'ro', 'ru', 'sv', 'tr'
-# html_search_language = 'en'
-
-# A dictionary with options for the search language support, empty by default.
-# Now only 'ja' uses this config value
-# html_search_options = {'type': 'default'}
-
-# The name of a javascript file (relative to the configuration directory) that
-# implements a search results scorer. If empty, the default will be used.
-# html_search_scorer = 'scorer.js'
-
 # Output file base name for HTML help builder.
 htmlhelp_basename = "PyJWTdoc"
 
-# -- Options for LaTeX output ---------------------------------------------
-
-latex_elements = {
-    # The paper size ('letterpaper' or 'a4paper').
-    #'papersize': 'letterpaper',
-    # The font size ('10pt', '11pt' or '12pt').
-    #'pointsize': '10pt',
-    # Additional stuff for the LaTeX preamble.
-    #'preamble': '',
-    # Latex figure (float) alignment
-    #'figure_align': 'htbp',
-}
-
-# Grouping the document tree into LaTeX files. List of tuples
-# (source start file, target name, title,
-#  author, documentclass [howto, manual, or own class]).
-latex_documents = [
-    (
-        master_doc,
-        "PyJWT.tex",
-        u"PyJWT Documentation",
-        u"José Padilla",
-        "manual",
-    )
-]
-
-# The name of an image file (relative to this directory) to place at the top of
-# the title page.
-# latex_logo = None
-
-# For "manual" documents, if this is true, then toplevel headings are parts,
-# not chapters.
-# latex_use_parts = False
-
-# If true, show page references after internal links.
-# latex_show_pagerefs = False
-
-# If true, show URL addresses after external links.
-# latex_show_urls = False
-
-# Documents to append as an appendix to all manuals.
-# latex_appendices = []
-
-# If false, no module index is generated.
-# latex_domain_indices = True
-
 
 # -- Options for manual page output ---------------------------------------
 
@@ -278,9 +115,6 @@ def get_version(package):
 # (source start file, name, description, authors, manual section).
 man_pages = [(master_doc, "pyjwt", u"PyJWT Documentation", [author], 1)]
 
-# If true, show URL addresses after external links.
-# man_show_urls = False
-
 
 # -- Options for Texinfo output -------------------------------------------
 
@@ -298,15 +132,3 @@ def get_version(package):
         "Miscellaneous",
     )
 ]
-
-# Documents to append as an appendix to all manuals.
-# texinfo_appendices = []
-
-# If false, no module index is generated.
-# texinfo_domain_indices = True
-
-# How to display URL addresses: 'footnote', 'no', or 'inline'.
-# texinfo_show_urls = 'footnote'
-
-# If true, do not generate a @detailmenu in the "Top" node's menu.
-# texinfo_no_detailmenu = False
diff --git a/docs/faq.rst b/docs/faq.rst
index a5eb1396..e8fb177e 100644
--- a/docs/faq.rst
+++ b/docs/faq.rst
@@ -28,11 +28,3 @@ extract the public or private keys from a x509 certificate in PEM format.
     cert_obj = load_pem_x509_certificate(cert_str, default_backend())
     public_key = cert_obj.public_key()
     private_key = cert_obj.private_key()
-
-
-I'm using Google App Engine and can't install `cryptography`, what can I do?
-----------------------------------------------------------------------------
-
-Some platforms like Google App Engine don't allow you to install libraries
-that require C extensions to be built (like `cryptography`). If you're deploying
-to one of those environments, you should check out :ref:`legacy-deps`
diff --git a/docs/requirements-docs.txt b/docs/requirements-docs.txt
deleted file mode 100644
index 82133027..00000000
--- a/docs/requirements-docs.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-sphinx
-sphinx_rtd_theme
diff --git a/docs/usage.rst b/docs/usage.rst
index 131e67bc..87269e32 100644
--- a/docs/usage.rst
+++ b/docs/usage.rst
@@ -2,7 +2,7 @@ Usage Examples
 ==============
 
 Encoding & Decoding Tokens with HS256
----------------------------------
+-------------------------------------
 
 .. code-block:: python
 
@@ -14,7 +14,7 @@ Encoding & Decoding Tokens with HS256
     {'some': 'payload'}
 
 Encoding & Decoding Tokens with RS256 (RSA)
----------------------------------
+-------------------------------------------
 
 .. code-block:: python
 
@@ -27,7 +27,7 @@ Encoding & Decoding Tokens with RS256 (RSA)
     {'some': 'payload'}
 
 Specifying Additional Headers
----------------------------------
+-----------------------------
 
 .. code-block:: python
 
@@ -36,7 +36,7 @@ Specifying Additional Headers
 
 
 Reading the Claimset without Validation
------------------------------------------
+---------------------------------------
 
 If you wish to read the claimset of a JWT without performing validation of the
 signature or any of the registered claim names, you can set the ``verify``
diff --git a/setup.py b/setup.py
index 8d06af5a..c672f72c 100755
--- a/setup.py
+++ b/setup.py
@@ -31,13 +31,14 @@
 ]
 INSTALL_REQUIRES = []
 EXTRAS_REQUIRE = {
-    "jwks-client": ["requests"],
+    "docs": ["sphinx", "sphinx-rtd-theme", "zope.interface"],
     "tests": [
         "coverage[toml]>=5.0.2",
         "pytest>=4.3.0,<5.0.0",
         "requests-mock>=1.7.0,<2.0.0",
     ],
     "cryptography": ["cryptography >= 1.4"],
+    "jwks-client": ["requests"],
 }
 
 EXTRAS_REQUIRE["dev"] = (
diff --git a/tox.ini b/tox.ini
index 13124095..7a140bc6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,7 @@ python =
     2.7: py27
     3.5: py35
     3.6: py36
-    3.7: py37
+    3.7: py37, docs
     3.8: py38, lint, manifest, typing
 
 
@@ -23,6 +23,7 @@ envlist =
     py{35,36,37,38}-crypto
     py{35,36,37,38}-nocrypto
     manifest
+    docs
     pypi-description
     coverage-report
 isolated_build = True
@@ -35,6 +36,15 @@ extras =
 commands = coverage run -m pytest {posargs}
 
 
+[testenv:docs]
+basepython = python3.7
+extras = docs
+commands =
+    sphinx-build -n -T -W -b html -d {envtmpdir}/doctrees docs docs/_build/html
+    sphinx-build -n -T -W -b doctest -d {envtmpdir}/doctrees docs docs/_build/html
+    python -m doctest README.rst
+
+
 [testenv:typing]
 basepython = python3.8
 extras = dev