diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
new file mode 100644
index 0000000..52e191d
--- /dev/null
+++ b/.github/workflows/codeql.yml
@@ -0,0 +1,42 @@
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+  schedule:
+    # 17:00 on Friday (UTC)
+    - cron: "00 17 * * 5"
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'python' ]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: ${{ matrix.language }}
+          queries: +security-and-quality
+
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v3
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+        with:
+          category: "/language:${{ matrix.language }}"
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..b049b7c
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,43 @@
+name: CI
+
+on:
+  push:
+    branches: [ "master", "ci-*" ]
+  pull_request:
+    branches: [ "master" ]
+  schedule:
+    # 17:00 on Friday (UTC)
+    - cron: "00 17 * * 5"
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
+      fail-fast: false
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --editable '.[develop,docs]'
+      shell: bash
+
+    - name: Check linting and type annotations
+      run: |
+        python -m flake8 src tests
+        python -m mypy src tests
+      shell: bash
+
+    - name: Run tests
+      if: success() || failure()
+      run: |
+        python -m pytest -v -s src tests
+      shell: bash
diff --git a/readthedocs.yml b/.readthedocs.yml
similarity index 74%
rename from readthedocs.yml
rename to .readthedocs.yml
index 0c49bb5..140fc04 100644
--- a/readthedocs.yml
+++ b/.readthedocs.yml
@@ -1,5 +1,3 @@
-formats:
-    - none
 build:
     image: latest
 python:
@@ -7,5 +5,7 @@ python:
    # Note that pip_install is buggy, but setup_py_install will not take into
    # account any dependencies from setup.py. *All* dependencies must be
    # declared in docs/rtd_environment.yml
-   setup_py_install: true
-   pip_install: false
+   #setup_py_install: true
+   pip_install: true
+   extra_requirements:
+     - dev
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 3dfbdcc..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,17 +0,0 @@
-# Config file for automatic testing at travis-ci.org
-
-language: python
-python:
-  - 3.6
-  - 3.5
-  - 3.4
-  - 3.3
-
-install:
-  - pip install -e .[dev]
-  - pip install coveralls
-
-script:
-  - py.test --doctest-modules --cov=doi src tests
-after_success:
-  - coveralls
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..dd8885f
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,7 @@
+v0.2
+====
+
+- Remove support for python 3.4 and lower.
+- Add type annotations.
+- Simplify `validate_doi` to just raise a `404` error in case
+  something went wrong.
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 1c1de3d..4886204 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -13,7 +13,7 @@ Types of Contributions
 Report Bugs
 ~~~~~~~~~~~
 
-Report bugs at https://github.com/alejandrogallo/doi/issues.
+Report bugs at https://github.com/papis/python-doi/issues.
 
 If you are reporting a bug, please include:
 
@@ -37,7 +37,7 @@ articles, and such.
 Submit Feedback
 ~~~~~~~~~~~~~~~
 
-The best way to send feedback is to file an issue at https://github.com/alejandrogallo/doi/issues.
+The best way to send feedback is to file an issue at https://github.com/papis/python-doi/issues.
 
 If you are proposing a feature:
 
@@ -51,7 +51,7 @@ Get Started!
 
 In short,
 
-1. Clone the repository from ``git@github.com:alejandrogallo/doi.git``
+1. Clone the repository from ``git@github.com:papis/python-doi.git``
 2. Fork the repo on GitHub to your personal account.
 3. Add your fork as a remote.
 4. Pull in the latest changes from the master branch.
@@ -77,6 +77,6 @@ Before you submit a pull request, check that it meets these guidelines:
 2. If the pull request adds functionality, the docs should be updated. Put
    your new functionality into a function with a docstring, and add the
    feature to the list in README.rst.
-3. Check https://travis-ci.org/alejandrogallo/doi/pull_requests
+3. Check https://travis-ci.org/papis/python-doi/pull_requests
    and make sure that the tests pass for all supported Python versions.
 
diff --git a/MANIFEST.in b/MANIFEST.in
deleted file mode 100644
index 2d4499e..0000000
--- a/MANIFEST.in
+++ /dev/null
@@ -1,11 +0,0 @@
-graft src
-include AUTHORS.rst
-include CONTRIBUTING.rst
-include LICENSE
-include README.rst
-
-recursive-include tests *
-recursive-exclude * __pycache__
-recursive-exclude * *.py[co]
-
-recursive-include docs *.rst conf.py Makefile make.bat *.jpg *.png *.gif
diff --git a/Makefile b/Makefile
index c300533..7e98982 100644
--- a/Makefile
+++ b/Makefile
@@ -1,460 +1,30 @@
+PYTHON?=python -X dev
 
-# File: common-makefile/src/version.m4
-MAKEFILE_VERSION = v0.0.1-21-g392d792
-MAKEFILE_DATE = 31-07-2017 15:47
-MAKEFILE_AUTHOR = Alejandro Gallo
-MAKEFILE_URL = https://github.com/alejandrogallo/python-makefile
-MAKEFILE_LICENSE = GPLv3
+all: help
 
-
-
-
-## <<HELP
-#
-#                            Python Makefile
-#
-## HELP
-
-# Local configuration
--include config.mk
-
-CLEAN_FILES += \
-$(shell find . -name *.pyc) \
-$(shell find . -name *.pyo) \
-$(shell find . -name __pycache__) \
-$(wildcard test_* ) \
-
-# File: common-makefile/src/os.m4
-# Recognise OS
-ifeq ($(shell uname),Linux)
-LINUX := 1
-OSX   :=
-else
-LINUX :=
-OSX   := 1
-endif
-
-
-
-
-# File: common-makefile/src/shell-utils.m4
-
-# Shell used
-SH ?= bash
-# Alias for `SHELL'
-SHELL ?= $(SH)
-# Python interpreter
-PY ?= python
-# Alias for `PY'
-PYTHON ?= $(PY)
-# Perl command
-PERL ?= perl
-# Grep program version
-GREP ?= grep
-# Find utility
-FIND ?= find
-# `sed` program version
-SED ?= $(if $(OSX),gsed,sed)
-# `awk` program to use
-AWK ?= $(if $(OSX),gawk,awk)
-# For creating tags
-CTAGS ?= ctags
-# To get complete paths
-READLINK ?= $(if $(OSX),greadlink,readlink)
-# `xargs` program to use
-XARGS ?= xargs
-# `tr` program to use
-TR ?= tr
-# `git` version to use
-GIT ?= git
-# `which` program to use
-WHICH ?= which
-# `sort` program to use
-SORT ?= sort
-# `uniq` program to use
-UNIQ ?= uniq
-# `Makefile` binary
-MAKE ?= $(or $(MAKE),make)
-# `rm` command
-RM ?= rm
-# C++ compiler
-CXX ?= g++
-# C compiler
-CC ?= gcc
-# Fortran compiler
-FC ?= gfortran
-
-
-
-# File: common-makefile/src/log.m4
-
-# If secondary programs output is shown
-QUIET ?= 0
-# If the log messages should be also muted
-QQUIET     ?=
-# If the commands issued should be printed write `DEBUG=1` if you want to see
-# all commands.
-DEBUG      ?=
-# For coloring
-TPUT       ?= $(shell $(WHICH) tput 2> /dev/null)
-# If messages should have color
-WITH_COLOR ?= 1
-
-ifneq ($(strip $(QUIET)),0)
-FD_OUTPUT = 2>&1 > /dev/null
-else
-FD_OUTPUT =
-endif
-
-ifdef DEBUG
-DBG_FLAG =
-DBG_FILE ?= .makefile-dbg
-$(shell date | $(SED) "p; s/./=/g" > $(DBG_FILE))
-else
-DBG_FLAG = @
-DBG_FILE =
-endif
-
-define log-debug
->> $(or $(DBG_FILE),/dev/null) echo
-endef
-
-# Print commands like [CMD]
-define print-cmd-name
-"[$(COLOR_LB) \
-$(shell \
-	if test "$(1)" = g++; then \
-		echo -n GXX; \
-	elif test "$(1)" = gcc; then \
-		echo -n GCC; \
-	elif test "$(1)" = icc; then \
-		echo -n ICC; \
-	elif test "$(1)" = cc; then \
-		echo -n CC; \
-	elif test "$(1)" = povray; then \
-		echo -n POV; \
-	elif test "$(1)" = perl; then \
-		echo -n PL; \
-	elif test "$(1)" = perl5; then \
-		echo -n PL5; \
-	elif test "$(1)" = ruby; then \
-		echo -n RB; \
-	elif test "$(1)" = ruby2; then \
-		echo -n RB2; \
-	elif test "$(1)" = python; then \
-		echo -n PY; \
-	elif test "$(1)" = python2; then \
-		echo -n PY2; \
-	elif test "$(1)" = python3; then \
-		echo -n PY3; \
-	elif test "$(1)" = pdflatex; then \
-		echo -n pdfTeX; \
-	elif test "$(1)" = bash; then \
-		echo -n BASH; \
-	elif test "$(1)" = gnuplot; then \
-		echo -n GPT; \
-	elif test "$(1)" = mupdf; then \
-		echo -n muPDF; \
-	else \
-		echo -n "$(1)" | tr a-z A-Z ; \
-	fi
-)\
-$(COLOR_E)]"
-endef
-
-ifndef QQUIET
-
-ifeq ($(strip $(WITH_COLOR)),1)
-# Red
-COLOR_R         ?= $(if $(TPUT),$(shell $(TPUT) setaf 1),"\033[0;31m")
-# Green
-COLOR_G         ?= $(if $(TPUT),$(shell $(TPUT) setaf 2),"\033[0;32m")
-# Yellow
-COLOR_Y         ?= $(if $(TPUT),$(shell $(TPUT) setaf 3),"\033[0;33m")
-# Dark blue
-COLOR_DB        ?= $(if $(TPUT),$(shell $(TPUT) setaf 4),"\033[0;34m")
-# Lila
-COLOR_L         ?= $(if $(TPUT),$(shell $(TPUT) setaf 5),"\033[0;35m")
-# Light blue
-COLOR_LB        ?= $(if $(TPUT),$(shell $(TPUT) setaf 6),"\033[0;36m")
-# Empty color
-COLOR_E         ?= $(if $(TPUT),$(shell $(TPUT) sgr0),"\033[0m")
-ARROW           ?= @echo "$(COLOR_L)===>$(COLOR_E)"
-else
-ARROW           ?= @echo "===>"
-endif #WITH_COLOR
-
-ECHO            ?= @echo
-
-else
-ARROW           := @ > /dev/null echo
-ECHO            := @ > /dev/null echo
-endif #QQUIET
-
-
-
-
-
-
-# File: ctags.m4
-
-
-# ====================================
-# Ctags generation for latex documents
-# ====================================
-#
-# Generate a tags  file so that you can navigate  through the tags using
-# compatible editors such as emacs or (n)vi(m).
-#
-tags: ## Create python exhuberant ctags
-	$(CTAGS) --language-force=python -R *
-
-
-
-# File: install.m4
-
-
-# Old-style requirements file
-REQUIREMENTS ?= requirements.txt
-# Command to be run when make `install` is run
-INSTALL_COMMAND ?= $(PYTHON) setup.py install
-# Command to be run when make `install-local` is run
-INSTALL_LOCAL_COMMAND ?= $(PYTHON) setup.py install --user
-# Command to be run when make `install-dev` is run
-INSTALL_DEV_COMMAND ?= $(PYTHON) setup.py develop
-# Command to be run when make `install-dev-local` is run
-INSTALL_DEV_LOCAL_COMMAND ?= $(PYTHON) setup.py develop --user
-# Command to be run when make `uninstall` is run
-UNINSTALL_COMMAND ?= $(PIP) uninstall $(shell $(PYTHON) setup.py --name)
-# Command to be run when make `install-deps` is run
-INSTALL_DEPS_COMMAND ?= $(PIP) install -r requirements.txt
-# Command to be run when make `install-deps-local` is run
-INSTALL_DEPS_LOCAL_COMMAND ?= $(PIP) install --user -r requirements.txt
-install-dev-local: ## Install developement version locally
-	$(ARROW) Installing development version locally
-	$(DBG_FLAG)$(INSTALL_DEV_LOCAL_COMMAND)
-
-install-dev: ## Install developement version
-	$(ARROW) Installing development version
-	$(DBG_FLAG)$(INSTALL_DEV_COMMAND)
-
-install-local: ## Install the package locally
-	$(ARROW) Installing locally
-	$(DBG_FLAG)$(INSTALL_LOCAL_COMMAND)
-
-install: ## Install the package
-	$(ARROW) Installing...
-	$(DBG_FLAG)$(INSTALL_COMMAND)
-
-uninstall: ## Uninstall the package
-	$(ARROW) Uninstalling...
-	$(DBG_FLAG)$(UNINSTALL_COMMAND)
-
-install-deps-local: ## Install python requirements locally
-	$(ARROW) Installing dependencies...
-	$(DBG_FLAG)$(INSTALL_DEPS_LOCAL_COMMAND)
-
-install-deps: ## Install python requirements
-	$(ARROW) Installing dependencies...
-	$(DBG_FLAG)$(INSTALL_DEPS_COMMAND)
-
-
-
-# File: lint.m4
-
-
-# Linter program
-PY_LINTER ?= flake8
-# ============
-# Check syntax
-# ============
-#
-# It checks the syntax (lints) of all the tex sources using the program in the
-# TEX_LINTER variable.
-#
-lint: ## Check syntax of sources
-	$(PY_LINTER)
-
-
-
-# File: doc.m4
-
-
-doc: ## Create documentation
-	make -C doc/ html
-
-doc-%:
-	make -C doc/ $*
-
-update-gh-pages: ## Update github pages
-	@echo "Warning: Black magic in action"
-	git push origin $$(git subtree split --prefix doc/build/html/ master):gh-pages --force
-
-
-
-
-# File: test.m4
-
-
-# Command to run for `make test`
-TEST_COMMAND ?= $(PYTHON) setup.py test
-test: ## Run the tests
-	$(DBG_FLAG)$(TEST_COMMAND)
-
-
-
-# File: virtualenv.m4
-
-
-ENV ?=
-ENV_FOLDER ?= env
-ENV_PIP ?= $(ENV_FOLDER)/bin/pip
-ENV_PYTHON ?= $(ENV_FOLDER)/bin/python
-VIRTUALENV ?= virtualenv
-
-ifdef ENV
-PYTHON = $(ENV_PYTHON)
-PIP = $(ENV_PIP)
-DEPENDENCIES += virtualenv
-DIST_DEPENDENCIES += virtualenv
-endif
-
-virtualenv: $(ENV_FOLDER) ## Create the python virtual environment
-$(ENV_FOLDER):
-	$(ARROW) "Creating virtual environment in '$(ENV_FOLDER)' \
-		with python executable '$(PYTHON)'"
-	$(DBG_FLAG)$(VIRTUALENV) -p $(PYTHON) $(ENV_FOLDER)
-
-
-
-
-# File: common-makefile/src/update.m4
-
-
-MAKEFILE_UPDATE_URL ?= https://raw.githubusercontent.com/alejandrogallo/python-makefile/master/dist/Makefile
-
-
-# ===============================
-# Update the makefile from source
-# ===============================
-#
-# You can always get the  latest `Makefile` version using this target.  You may
-# override the `MAKEFILE_UPDATE_URL` to  any path where you save your own
-# personal makefile
-#
-update: ## Update the makefile from the repository
-	$(ARROW) "Getting makefile from $(MAKEFILE_UPDATE_URL)"
-	$(DBG_FLAG)wget $(MAKEFILE_UPDATE_URL) -O Makefile
-
-
-
-
-# File: common-makefile/src/clean.m4
-
-
-# Remove command flags
-RM_FLAGS ?= -rf
-
-# Default clean file to be cleaned
-DEFAULT_CLEAN_FILES ?=
-
-# Files to be cleaned
-CLEAN_FILES ?= $(DEFAULT_CLEAN_FILES)
-
-# =============
-# Main cleaning
-# =============
-#
-# This does a main cleaning of the produced auxiliary files.  Before using it
-# check which files are going to be cleaned up.
-#
-clean: ## Remove build and temporary files
-	$(ARROW) Cleaning up...
-	$(DBG_FLAG) {\
-		for file in $(CLEAN_FILES); do \
-			test -e $$file && { \
-				$(RM) $(RM_FLAGS) $$file &&      \
-				echo $(call print-cmd-name,RM) "$$file";\
-		 } || : ; \
-		done \
-	}
-
-
-
-
-# File: common-makefile/src/print-variable.m4
-
-
-# This is used for printing defined variables from Some other scripts. For
-# instance if you want to know the value of the `PDF_VIEWER` defined in the
-# Makefile, then you would do
-# ```
-#    make print-PDF_VIEWER
-# ```
-# and this would output `PDF_VIEWER=mupdf` for instance.
-FORCE:
-print-%:
-	$(DBG_FLAG)echo '$*=$($*)'
-
-# =====================================
-# Print a variable used by the Makefile
-# =====================================
-#
-# For debugging purposes it is useful to print out some variables that the
-# makefile is using, for that just type `make print` and you will be prompted
-# to insert the name of the variable that you want to know.
-#
-FORCE:
-print: ## Print a variable
-	$(DBG_FLAG)read -p "Variable to print: " variable && \
-		$(MAKE) --no-print-directory print-$$variable
-
-
-
-
-# File: common-makefile/src/help.m4
-
-
-
-# ================
-# Print quick help
-# ================
-#
-# It prints a quick help in the terminal
-help: ## Prints help for targets with comments
-	$(DBG_FLAG)$(or $(AWK),awk) ' \
-		BEGIN {FS = ":.*?## "}; \
-		/^## *<<HELP/,/^## *HELP/ { \
-			help=$$1; \
-			gsub("#","",help); \
-			if (! match(help, "HELP")) \
-				print help ; \
-		}; \
-		/^[a-zA-Z0-9_\-.]+:.*?## .*$$/{ \
-			printf "\033[36m%-30s\033[0m %s\n", $$1, $$2 ; \
-		};' \
-		$(MAKEFILE_LIST)
+help: 								## Show this help
+	@echo -e "Specify a command. The choices are:\n"
+	@grep -E '^[0-9a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "  \033[0;36m%-18s\033[m %s\n", $$1, $$2}'
 	@echo ""
-	@echo "  $(MAKEFILE_VERSION)"
-	@echo "  $(MAKEFILE_URL)"
-	@echo "  Copyright $(MAKEFILE_AUTHOR) $(MAKEFILE_LICENSE) $(MAKEFILE_DATE)"
-	@echo ""
-
-
-
-
-# File: common-makefile/src/help-target.m4
-
-
-FORCE:
-help-%:
-	$(DBG_FLAG)$(SED) -n "/[#] [=]\+/,/^$*: / { /"$*":/{q}; p; } " $(MAKEFILE_LIST) \
-		| tac \
-		| sed -n "1,/===/ {/===/n; s/^# //p}" \
-		| tac \
-		| sed -n "p; 1s/./=/gp; 1a\ "
-
-
-
-
-# vim: cc=80
+.PHONY: help
+
+tags:								## Generate ctags for main codebase
+	ctags -f tags \
+		--recurse=yes \
+		--tag-relative=yes \
+		--fields=+l \
+		--kinds-python=-i \
+		--language-force=python \
+		papis
+.PHONY: tags
+
+pytest:								## Run pytest tests and doctests
+	$(PYTHON) -m pytest -v -s src tests
+
+flake8:								## Run flake8 (style checks)
+	$(PYTHON) -m flake8 src tests
+.PHONY: flake8
+
+mypy:								## Run mypy (type annotations)
+	$(PYTHON) -m mypy src tests
+.PHONY: mypy
diff --git a/README.rst b/README.rst
index ed5ede0..29d5e27 100644
--- a/README.rst
+++ b/README.rst
@@ -5,12 +5,12 @@ python-doi
    :alt: python-doi on the Python Package Index
    :target: https://pypi.python.org/pypi/python-doi
 
-.. image:: https://img.shields.io/travis/alejandrogallo/python-doi.svg
+.. image:: https://img.shields.io/travis/papis/python-doi.svg
    :alt: Travis Continuous Integration
-   :target: https://travis-ci.org/alejandrogallo/python-doi
-.. image:: https://coveralls.io/repos/github/alejandrogallo/python-doi/badge.svg?branch=master
+   :target: https://travis-ci.org/papis/python-doi
+.. image:: https://coveralls.io/repos/github/papis/python-doi/badge.svg?branch=master
    :alt: Coveralls
-   :target: https://coveralls.io/github/alejandrogallo/python-doi?branch=master
+   :target: https://coveralls.io/github/papis/python-doi?branch=master
 .. image:: https://readthedocs.org/projects/python-doi/badge/?version=latest
    :alt: Documentation Status
    :target: https://python-doi.readthedocs.io/en/latest/?badge=latest
@@ -44,9 +44,9 @@ To install the latest development version of python-doi from `Github`_.
 
 .. code-block:: console
 
-    $ pip install git+https://github.com/alejandrogallo/python-doi.git@master#egg=doi
+    $ pip install git+https://github.com/papis/python-doi.git@master#egg=doi
 
-.. _Github: https://github.com/alejandrogallo/python-doi
+.. _Github: https://github.com/papis/python-doi
 
 Usage
 -----
diff --git a/docs/api.rst b/docs/api.rst
new file mode 100644
index 0000000..3266019
--- /dev/null
+++ b/docs/api.rst
@@ -0,0 +1,5 @@
+API
+===
+
+.. automodule:: doi
+    :members:
diff --git a/docs/conf.py b/docs/conf.py
index a8f8866..e9c303f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -40,6 +40,7 @@
     'sphinx.ext.todo',
     'dollarmath',
     'sphinx.ext.inheritance_diagram',
+    'sphinx_autodoc_typehints',
 ]
 if os.getenv('SPELLCHECK'):
     extensions += 'sphinxcontrib.spelling',
@@ -66,8 +67,8 @@
 
 pygments_style = 'sphinx'
 extlinks = {
-    'issue': ('https://github.com/alejandrogallo/doi/issues/%s', '#'),
-    'pr': ('https://github.com/alejandrogallo/doi/pull/%s', 'PR #'),
+    'issue': ('https://github.com/papis/python-doi/issues/%s', '#'),
+    'pr': ('https://github.com/papis/python-doi/pull/%s', 'PR #'),
 }
 
 # autodoc settings
diff --git a/docs/index.rst b/docs/index.rst
index 813567c..d5b346c 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -8,8 +8,7 @@ Welcome to python-doi's documentation!
    readme
    contributing
    authors
-   API
-===
+   api
 
 .. toctree::
    :maxdepth: 1
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..faba3d3
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,88 @@
+[build-system]
+build-backend = "hatchling.build"
+requires = [
+    "hatchling>=1.10",
+]
+
+[project]
+name = "python-doi"
+version = "0.2.0"
+description = "Python package to work with Document Object Identifiers (DOIs)"
+readme = "README.rst"
+keywords = [
+    "doi",
+]
+license = { text = "GPL-3.0-or-later" }
+maintainers = [{ name = "Alejandro Gallo", email = "aamsgallo@gmail.com" }]
+authors = [{ name = "Alejandro Gallo", email = "aamsgallo@gmail.com" }]
+requires-python = ">=3.8"
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
+    "Natural Language :: English",
+    "Operating System :: OS Independent",
+    "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Topic :: Utilities",
+]
+
+[project.optional-dependencies]
+develop = [
+    "flake8",
+    "flake8-bugbear",
+    "Flake8-pyproject",
+    "flake8-quotes",
+    "mypy>=0.7",
+    "pep8-naming",
+    "pytest",
+    "pytest-cov",
+    "python-coveralls",
+]
+docs = [
+    "sphinx>=4",
+    "sphinx_rtd_theme>=1",
+]
+# For solving client-side challenges on DDoS-protected sites
+# (eg those using CloudFlare)
+challenges = [
+    "cloudscraper",
+]
+
+[project.urls]
+Repository = "https://github.com/papis/python-doi"
+
+[tool.hatch.build.targets.sdist]
+exclude = [".github", "docs/build"]
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/doi"]
+
+[tool.flake8]
+select = ["B", "D", "E", "F", "N", "Q", "W"]
+extend-ignore = ["B019", "E123", "N818", "W503"]
+max-line-length = 88
+inline-quotes = "double"
+multiline-quotes = "double"
+
+[tool.pytest.ini_options]
+addopts = [
+    "--doctest-modules",
+    "--cov=src/doi",
+    "--ignore=docs",
+]
+markers = [
+    "net: marks tests that call use the net"
+]
+
+[tool.mypy]
+strict = true
+show_column_numbers = true
+hide_error_codes = false
+pretty = true
+warn_unused_ignores = false
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index d7fc0e9..0000000
--- a/setup.cfg
+++ /dev/null
@@ -1,9 +0,0 @@
-[bdist_wheel]
-universal = 1
-
-[flake8]
-exclude = docs
-
-[tool:pytest]
-collect_ignore = ['setup.py']
-
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 06915f0..0000000
--- a/setup.py
+++ /dev/null
@@ -1,56 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-"""The setup script."""
-
-from setuptools import setup, find_packages
-
-
-def get_version(filename):
-    """Extract the package version"""
-    with open(filename) as in_fh:
-        for line in in_fh:
-            if line.startswith('__version__'):
-                return line.split('=')[1].strip()[1:-1]
-    raise ValueError("Cannot extract version from %s" % filename)
-
-
-with open('README.rst') as readme_file:
-    readme = readme_file.read()
-
-requirements = []
-
-dev_requirements = [
-    'coverage', 'pytest', 'pytest-cov==2.5.0', 'twine', 'pep8',
-    'flake8', 'wheel', 'sphinx', 'sphinx-autobuild', 'sphinx_rtd_theme']
-
-version = get_version('./src/doi/__init__.py')
-
-setup(
-    author="Alejandro Gallo",
-    author_email='aamsgallo@gmail.com',
-    classifiers=[
-        'Development Status :: 2 - Pre-Alpha',
-        'Intended Audience :: Developers',
-        'License :: OSI Approved :: GNU General Public License v3 (GPLv3)',
-        'Natural Language :: English',
-        'Programming Language :: Python :: 3.4',
-        'Programming Language :: Python :: 3.5',
-        'Programming Language :: Python :: 3.6',
-    ],
-    description="Python package to work with Document Object Identifier (doi)",
-    install_requires=requirements,
-    extras_require={
-        'dev': dev_requirements,
-    },
-    license="GNU General Public License v3",
-    long_description=readme,
-    include_package_data=True,
-    keywords='doi',
-    name='python-doi',
-    packages=find_packages(where="src"),
-    package_dir={"": "src"},
-    url='https://github.com/alejandrogallo/doi',
-    version=version,
-    zip_safe=False,
-)
diff --git a/src/doi/__init__.py b/src/doi/__init__.py
index 24b69b8..cd19507 100644
--- a/src/doi/__init__.py
+++ b/src/doi/__init__.py
@@ -1,113 +1,97 @@
 import re
+import sys
 import logging
 
+from typing import Optional
 
-__version__ = '0.1.0'
 
+__version__ = "0.2.0"
+logger = logging.getLogger("doi")   # type: logging.Logger
 
-logger = logging.getLogger("doi")
 
-
-def pdf_to_doi(filepath, maxlines=float('inf')):
-    """Try to get doi from a filepath, it looks for a regex in the binary
-    data and returns the first doi found, in the hopes that this doi
+def pdf_to_doi(filepath: str, maxlines: Optional[int] = None) -> Optional[str]:
+    """Try to get DOI from a filepath. It looks for a regex in the binary
+    data and returns the first DOI found, in the hopes that this DOI
     is the correct one.
 
-    :param filepath: Path to the pdf file
-    :type  filepath: str
+    :param filepath: Path to the pdf file.
     :param maxlines: Maximum number of lines that should be checked
-        For some documnets, it would spend a long time trying to look for
-        a doi, and dois in the middle of documents don't tend to be the correct
-        doi of the document.
-    :type  maxlines: int
-    :returns: DOI or None
-    :rtype:  str or None
+        For some documents, it could spend a long time trying to look for
+        a DOI, and DOIs in the middle of documents don't tend to be the correct
+        DOI of the document.
+    :returns: DOI or ``None``.
     """
-    with open(filepath, 'rb') as fd:
+    if maxlines is None:
+        maxlines = sys.maxsize
+
+    with open(filepath, "rb") as fd:
         for j, line in enumerate(fd):
-            doi = find_doi_in_text(line.decode('ascii', errors='ignore'))
+            doi = find_doi_in_text(line.decode("ascii", errors="ignore"))
             if doi:
                 return doi
             if j > maxlines:
                 return None
-        else:
-            return None
-
-
-def validate_doi(doi):
-    """We check that the DOI can be resolved by official means.  If so, we
-    return the resolved URL, otherwise, we return None (which means the DOI is
-    invalid).
+        return None
 
-    http://www.doi.org/factsheets/DOIProxy.html
 
-    :param doi: Doi identificator
-    :type  doi: str
-    :returns: It returns the url assigned to the doi if everything went right
-    :rtype: str
+def validate_doi(doi: str) -> Optional[str]:
+    """We check that the DOI can be resolved by
+    `official means <http://www.doi.org/factsheets/DOIProxy.html>`_. If so, we
+    return the resolved URL, otherwise, we return ``None`` (which means the
+    DOI is invalid).
 
-    :raises ValueError: Whenever the doi is not valid
+    :param doi: Identifier.
+    :returns: The URL assigned to the DOI or ``None``.
     """
-    from urllib.error import HTTPError, URLError
+    from urllib.error import HTTPError
     import urllib.request
     import urllib.parse
     import json
     url = "https://doi.org/api/handles/{doi}".format(doi=doi)
-    logger.debug('handle url %s' % url)
+    logger.debug("handle url %s", url)
     request = urllib.request.Request(url)
 
     try:
         result = json.loads(urllib.request.urlopen(request).read().decode())
-        if 'values' in result:
-            url = [v['data']['value']
-                    for v in result['values'] if v.get('type') == 'URL']
-            return url[0] if url else None
     except HTTPError:
-        raise ValueError('HTTP 404: DOI not found')
-    except URLError as e:
-        raise ValueError(e)
-
-    response_code = int(result["responseCode"])
-    if response_code in [1, 200]:
-        # HTTP 200 all ok
-        logger.debug('HTTP 200: valid doi')
-    elif response_code == 2:
-        raise ValueError('HTTP 500: Interal DOI server error')
-    elif response_code == 100:
-        raise ValueError('HTTP 404: DOI not found')
+        raise ValueError("HTTP 404: DOI not found")
     else:
-        raise ValueError('Something unexpected happened')
+        urls = [v["data"]["value"]
+                for v in result["values"] if v.get("type") == "URL"]
+        return urls[0] if urls else None
 
 
-def get_clean_doi(doi):
-    """Check if doi is actually a url and in that case just get
-    the exact doi.
+def get_clean_doi(doi: str) -> str:
+    """Check if the DOI is actually a URL and in that case just get
+    the exact DOI.
 
-    :doi: String containing a doi
-    :returns: The pure doi
+    :param doi: String containing a DOI.
+    :returns: The extracted DOI.
     """
-    doi = re.sub(r'%2F', '/', doi)
+    doi = re.sub(r"%2F", "/", doi)
     # For pdfs
-    doi = re.sub(r'\)>', ' ', doi)
-    doi = re.sub(r'\)/S/URI', ' ', doi)
-    doi = re.sub(r'(/abstract)', '', doi)
-    doi = re.sub(r'\)$', '', doi)
+    doi = re.sub(r"\)>", " ", doi)
+    doi = re.sub(r"\)/S/URI", " ", doi)
+    doi = re.sub(r"(/abstract)", "", doi)
+    doi = re.sub(r"\)$", "", doi)
     return doi
 
 
-def find_doi_in_text(text):
-    """
-    Try to find a doi in a text
+def find_doi_in_text(text: str) -> Optional[str]:
+    """Try to find a DOI in a text.
+
+    :param text: Text in which to look for DOI.
+    :returns: A DOI, if found, otherwise ``None``.
     """
     text = get_clean_doi(text)
     forbidden_doi_characters = r'"\s%$^\'<>@,;:#?&'
     # Sometimes it is in the javascript defined
     var_doi = re.compile(
-        r'doi(.org)?'
-        r'\s*(=|:|/|\()\s*'
-        r'("|\')?'
-        r'(?P<doi>[^{fc}]+)'
-        r'("|\'|\))?'
+        r"doi(.org)?"
+        r"\s*(=|:|/|\()\s*"
+        r"(\"|')?"
+        r"(?P<doi>[^{fc}]+)"
+        r"(\"|'|\))?"
         .format(
             fc=forbidden_doi_characters
         ), re.I
@@ -118,20 +102,25 @@ def find_doi_in_text(text):
         try:
             m = next(miter)
             if m:
-                doi = m.group('doi')
+                doi = m.group("doi")
                 return get_clean_doi(doi)
         except StopIteration:
             pass
     return None
 
 
-def get_real_url_from_doi(doi):
+def get_real_url_from_doi(doi: str) -> Optional[str]:
+    """Get a URL corresponding to a DOI.
+
+    :param doi: Identifier.
+    :returns: A URL for the DOI. If the DOI is invalid, return ``None``.
+    """
     url = validate_doi(doi)
-    if not url:
+    if url is None:
         return url
 
-    m = re.match('.*linkinghub\.elsevier.*/pii/([A-Z0-9]+).*', url, re.I)
+    m = re.match(r".*linkinghub\.elsevier.*/pii/([A-Z0-9]+).*", url, re.I)
     if m:
-        return ('https://www.sciencedirect.com/science/article/abs/pii/{pii}'
+        return ("https://www.sciencedirect.com/science/article/abs/pii/{pii}"
                 .format(pii=m.group(1)))
     return url
diff --git a/src/doi/py.typed b/src/doi/py.typed
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_doi.py b/tests/test_doi.py
index be2acce..1049b8b 100644
--- a/tests/test_doi.py
+++ b/tests/test_doi.py
@@ -1,87 +1,164 @@
-"""Tests for `doi` package."""
-
 import os
-from pkg_resources import parse_version
+
+import requests
+try:
+    import cloudscraper
+except ImportError:
+    cloudscraper = None
+from urllib.parse import urlparse, urlunparse
+from warnings import warn
+
+import pytest
 
 from doi import (
-    validate_doi, find_doi_in_text, __version__, pdf_to_doi,
+    validate_doi, find_doi_in_text, pdf_to_doi,
     get_real_url_from_doi
 )
 
 
-def test_valid_version():
-    """Check that the package defines a valid __version__"""
-    assert parse_version(__version__) >= parse_version("0.1.0")
-
-
-def test_validate_doi():
-    data = [
-        ('10.1063/1.5081715',
-            'http://aip.scitation.org/doi/10.1063/1.5081715'),
-        ('10.1007%2FBF01451751',
-            'http://link.springer.com/10.1007/BF01451751'),
-        ('10.1103/PhysRevLett.49.57',
-            'https://link.aps.org/doi/10.1103/PhysRevLett.49.57'),
-        ('10.1080/14786442408634457',
-            'https://www.tandfonline.com/doi/full/10.1080/14786442408634457'),
-        ('10.1021/jp003647e', 'https://pubs.acs.org/doi/10.1021/jp003647e'),
-        ('10.1016/S0009-2614(97)04014-1',
-            'http://linkinghub.elsevier.com/retrieve/pii/S0009261497040141'),
+def simplify_url(u):
+    return urlparse(u)._replace(query='', fragment='')
+
+
+def resolve_redirects(u):
+    # Unconditionally upgrade to https, since some resolvers seem to require it
+    # If removed, it'd make sense to canonicalize in simplify_url instead to
+    # prevent spurious test failures
+    u = urlunparse(urlparse(u)._replace(scheme='https'))
+
+    if cloudscraper:
+        scraper = cloudscraper.create_scraper()
+        return simplify_url(scraper.get(u).url)
+
+    # Try emulating a browser to not get blocked
+    h = {'User-Agent': 'Mozilla/5.0'}
+    resp = requests.get(u, headers=h)
+    return simplify_url(resp.url)
+
+
+def normalize_eq(u, v, expect_diff=False):
+    if u == v:
+        return True
+    if not expect_diff:
+        warn(f"{u} textually differs from {v}, please update the relevant case.\n"
+             "Attempting to recover by resolving redirects")
+    return (simplify_url(u) == simplify_url(v)
+            or resolve_redirects(u) == resolve_redirects(v)
+            )
+
+
+def listmin(param):
+    if isinstance(param, list):
+        return min(param)
+    return ""
+
+
+@pytest.mark.net
+@pytest.mark.parametrize(
+    "needs_cloudscraper, urls", ids=listmin, argvalues=
+    [
+        (True,
+         ["http://pubs.aip.org/aip/jcp/article/150/7/074102/197572/Exact-two-component-equation-of-motion-coupled",  # noqa: E501
+          "http://pubs.aip.org/jcp/article/150/7/074102/197572/Exact-two-component-equation-of-motion-coupled",  # noqa: E501
+          "http://aip.scitation.org/doi/10.1063/1.5081715"
+         ]),
+     ]
+)
+def test_redirect(needs_cloudscraper, urls) -> None:
+    base = urls[0]
+    if needs_cloudscraper and cloudscraper is None:
+        pytest.skip(f"cloudscraper needed to solve CloudFlare challenge on {base}")
+    for other in urls[1:]:
+        assert normalize_eq(base, other, expect_diff=True)
+
+
+@pytest.mark.net
+@pytest.mark.parametrize(
+    "doi,url",
+    [
+        ("10.1063/1.5081715",
+         "https://pubs.aip.org/jcp/article/150/7/074102/197572/Exact-two-component-equation-of-motion-coupled"),  # noqa: E501
+        ("10.1007%2FBF01451751",
+         "http://link.springer.com/10.1007/BF01451751"),
+        ("10.1103/PhysRevLett.49.57",
+         "https://link.aps.org/doi/10.1103/PhysRevLett.49.57"),
+        ("10.1080/14786442408634457",
+         "https://www.tandfonline.com/doi/full/10.1080/14786442408634457"),
+        ("10.1021/jp003647e",
+         "https://pubs.acs.org/doi/10.1021/jp003647e"),
+        ("10.1016/S0009-2614(97)04014-1",
+         "https://linkinghub.elsevier.com/retrieve/pii/S0009261497040141"),
     ]
-    for doi, url in data:
-        assert(url == validate_doi(doi))
-
-    for doi in ['', 'asdf']:
-        try:
-            validate_doi(doi)
-        except ValueError as e:
-            assert(str(e) == 'HTTP 404: DOI not found')
-
-def test_get_real_url_from_doi():
-    data = [
-        ('10.1016/S0009-2614(97)04014-1',
-         'https://www.sciencedirect.com/science/'
-         'article/abs/pii/S0009261497040141'),
+)
+def test_validate_doi(doi, url) -> None:
+    assert normalize_eq(url, validate_doi(doi))
+
+
+@pytest.mark.parametrize(
+    "doi",
+    [
+        "",
+        "asdf"
+    ]
+)
+def test_validate_invalid_doi(doi) -> None:
+    try:
+        validate_doi(doi)
+    except ValueError as e:
+        assert str(e) == "HTTP 404: DOI not found"
+
+
+@pytest.mark.net
+@pytest.mark.parametrize(
+    "doi,url",
+    [
+        ("10.1016/S0009-2614(97)04014-1",
+         "https://www.sciencedirect.com/science/"
+         "article/abs/pii/S0009261497040141"),
     ]
-    for doi, url in data:
-        assert(url == get_real_url_from_doi(doi))
-
-
-def test_find_doi_in_line():
-    test_data = [
-        ('http://dx.doi.org/10.1063/1.881498', '10.1063/1.881498'),
-        ('http://dx.doi.org/10.1063%2F1.881498', '10.1063/1.881498'),
-        (2*'qer '+'var doi = "12345/12345.3"', '12345/12345.3'),
-        (2*'qer '+"var doi = '12345/12345.3';fas", '12345/12345.3'),
-        (2*'qer '+"var DoI = 12345%2F12345.3", '12345/12345.3'),
-        (2*'qer '+"var DoI : 12345%2F12345.3", '12345/12345.3'),
-        ('http://scitation.org/doi/10.1063/1.881498', '10.1063/1.881498'),
-        ('org/doi(10.1063/1.881498)', '10.1063/1.881498'),
-        ('/scitation.org/doi/10.1063/1.881498?234saf=34', '10.1063/1.881498'),
-        ('/scitation.org/doi/10.1063/1.88149 8?234saf=34', '10.1063/1.88149'),
-        ('/scitation.org/doi/10.1063/1.uniau12?as=234',
-            '10.1063/1.uniau12'),
-        ('https://doi.org/10.1093/analys/anw053' , '10.1093/analys/anw053'),
-        ('http://.scitation.org/doi/10.1063/1.mart(88)1498?asdfwer' ,
-            '10.1063/1.mart(88)1498'),
-        ('@ibook{doi:10.1002/9780470125915.ch2,', '10.1002/9780470125915.ch2'),
-        ('<rdf:Description rdf:about="" xmlns:dc="http://purl.org/dc/elements/1'
+)
+def test_get_real_url_from_doi(doi, url) -> None:
+    assert normalize_eq(url, get_real_url_from_doi(doi))
+
+
+@pytest.mark.parametrize(
+    "url, doi",
+    [
+        ("http://dx.doi.org/10.1063/1.881498", "10.1063/1.881498"),
+        ("http://dx.doi.org/10.1063%2F1.881498", "10.1063/1.881498"),
+        (2 * "qer " + "var doi = '12345/12345.3'", "12345/12345.3"),
+        (2 * "qer " + "var doi = '12345/12345.3';fas", "12345/12345.3"),
+        (2 * "qer " + "var DoI = 12345%2F12345.3", "12345/12345.3"),
+        (2 * "qer " + "var DoI : 12345%2F12345.3", "12345/12345.3"),
+        ("http://scitation.org/doi/10.1063/1.881498", "10.1063/1.881498"),
+        ("org/doi(10.1063/1.881498)", "10.1063/1.881498"),
+        ("/scitation.org/doi/10.1063/1.881498?234saf=34", "10.1063/1.881498"),
+        ("/scitation.org/doi/10.1063/1.88149 8?234saf=34", "10.1063/1.88149"),
+        ("/scitation.org/doi/10.1063/1.uniau12?as=234",
+         "10.1063/1.uniau12"),
+        ("https://doi.org/10.1093/analys/anw053", "10.1093/analys/anw053"),
+        ("http://.scitation.org/doi/10.1063/1.mart(88)1498?asdfwer",
+         "10.1063/1.mart(88)1498"),
+        ("@ibook{doi:10.1002/9780470125915.ch2,", "10.1002/9780470125915.ch2"),
+        ('<rdf:Description rdf:about="" xmlns:dc="http://purl.org/dc/elements'
          '.1/"><dc:format>application/pdf</dc:format><dc:identifier>'
-         'doi:10.1063/1.5079474</dc:identifier></rdf:Description>',
-            '10.1063/1.5079474'),
-        ('<(DOI:10.1002/9780470915.CH2)/S/URI,', '10.1002/9780470915.CH2'),
-        ('URL<(DOI:10.1002/9780470125915.CH2,', '10.1002/9780470125915.CH2'),
-        (r'A<</S/URI/URI(https://doi.org/10.1016/j.comptc.2018.10.004)>>/'
-         r'Border[0 0 0]/M(D:20181022082356+0530)/Rect[147.40158 594.36926'
-         r'347.24957 605.36926]/Subtype/Link/Type/A',
-            '10.1016/j.comptc.2018.10.004'),
-        ('doi(10.1038/s41535-018-0103-6;)', '10.1038/s41535-018-0103-6'),
+         "doi:10.1063/1.5079474</dc:identifier></rdf:Description>",
+         "10.1063/1.5079474"),
+        ("<(DOI:10.1002/9780470915.CH2)/S/URI,", "10.1002/9780470915.CH2"),
+        ("URL<(DOI:10.1002/9780470125915.CH2,", "10.1002/9780470125915.CH2"),
+        (r"A<</S/URI/URI(https://doi.org/10.1016/j.comptc.2018.10.004)>>/"
+         r"Border[0 0 0]/M(D:20181022082356+0530)/Rect[147.40158 594.36926"
+         r"347.24957 605.36926]/Subtype/Link/Type/A",
+         "10.1016/j.comptc.2018.10.004"),
+        ("doi(10.1038/s41535-018-0103-6;)", "10.1038/s41535-018-0103-6"),
     ]
-    for url, doi in test_data:
-        assert(find_doi_in_text(url) == doi)
+)
+def test_find_doi_in_line(url, doi) -> None:
+    assert find_doi_in_text(url) == doi
+
 
+def test_doi_from_pdf() -> None:
+    f = os.path.join(os.path.dirname(__file__), "resources", "doc.pdf")
 
-def test_doi_from_pdf():
-    f = os.path.join(os.path.dirname(__file__), 'resources', 'doc.pdf')
-    assert(os.path.exists(f))
-    assert(pdf_to_doi(f) == '10.1103/PhysRevLett.50.1998')
+    assert os.path.exists(f)
+    assert pdf_to_doi(f) == "10.1103/PhysRevLett.50.1998"