diff --git a/client/bin/__init__.py b/client/bin/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/client/bin/pypssl b/client/bin/pssl.py
old mode 100755
new mode 100644
similarity index 98%
rename from client/bin/pypssl
rename to client/bin/pssl.py
index 8c2b7a0..b06e19d
--- a/client/bin/pypssl
+++ b/client/bin/pssl.py
@@ -6,7 +6,7 @@ import pypssl
 import json
 
 
-if __name__ == '__main__':
+def main():
     parser = argparse.ArgumentParser(description='Query a Passive SSL instance.')
     parser.add_argument("--url", default='https://www.circl.lu/', help='URL where the passive SSL is running (no path).')
     parser.add_argument("-v", "--version", type=int, default=2, help='URL where the passive SSL is running (no path).')
@@ -28,3 +28,7 @@ if __name__ == '__main__':
         print(json.dumps(p.fetch_cert(args.fetch, make_datetime=False)))
     else:
         print('You didn\'t query anything...')
+
+
+if __name__ == '__main__':
+    main()
diff --git a/client/poetry.lock b/client/poetry.lock
new file mode 100644
index 0000000..8a41562
--- /dev/null
+++ b/client/poetry.lock
@@ -0,0 +1,108 @@
+[[package]]
+name = "certifi"
+version = "2020.12.5"
+description = "Python package for providing Mozilla's CA Bundle."
+category = "main"
+optional = false
+python-versions = "*"
+
+[[package]]
+name = "chardet"
+version = "4.0.0"
+description = "Universal encoding detector for Python 2 and 3"
+category = "main"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
+
+[[package]]
+name = "idna"
+version = "2.10"
+description = "Internationalized Domain Names in Applications (IDNA)"
+category = "main"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
+
+[[package]]
+name = "python-dateutil"
+version = "2.8.1"
+description = "Extensions to the standard Python datetime module"
+category = "main"
+optional = false
+python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,>=2.7"
+
+[package.dependencies]
+six = ">=1.5"
+
+[[package]]
+name = "requests"
+version = "2.25.1"
+description = "Python HTTP for Humans."
+category = "main"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
+
+[package.dependencies]
+certifi = ">=2017.4.17"
+chardet = ">=3.0.2,<5"
+idna = ">=2.5,<3"
+urllib3 = ">=1.21.1,<1.27"
+
+[package.extras]
+security = ["pyOpenSSL (>=0.14)", "cryptography (>=1.3.4)"]
+socks = ["PySocks (>=1.5.6,!=1.5.7)", "win-inet-pton"]
+
+[[package]]
+name = "six"
+version = "1.15.0"
+description = "Python 2 and 3 compatibility utilities"
+category = "main"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*"
+
+[[package]]
+name = "urllib3"
+version = "1.26.4"
+description = "HTTP library with thread-safe connection pooling, file post, and more."
+category = "main"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, <4"
+
+[package.extras]
+secure = ["pyOpenSSL (>=0.14)", "cryptography (>=1.3.4)", "idna (>=2.0.0)", "certifi", "ipaddress"]
+socks = ["PySocks (>=1.5.6,!=1.5.7,<2.0)"]
+brotli = ["brotlipy (>=0.6.0)"]
+
+[metadata]
+lock-version = "1.1"
+python-versions = "^3.6"
+content-hash = "20f507f4d6d4e764146721fc78541eccdff9e36c2534af753ebd4b51c8ede5b0"
+
+[metadata.files]
+certifi = [
+    {file = "certifi-2020.12.5-py2.py3-none-any.whl", hash = "sha256:719a74fb9e33b9bd44cc7f3a8d94bc35e4049deebe19ba7d8e108280cfd59830"},
+    {file = "certifi-2020.12.5.tar.gz", hash = "sha256:1a4995114262bffbc2413b159f2a1a480c969de6e6eb13ee966d470af86af59c"},
+]
+chardet = [
+    {file = "chardet-4.0.0-py2.py3-none-any.whl", hash = "sha256:f864054d66fd9118f2e67044ac8981a54775ec5b67aed0441892edb553d21da5"},
+    {file = "chardet-4.0.0.tar.gz", hash = "sha256:0d6f53a15db4120f2b08c94f11e7d93d2c911ee118b6b30a04ec3ee8310179fa"},
+]
+idna = [
+    {file = "idna-2.10-py2.py3-none-any.whl", hash = "sha256:b97d804b1e9b523befed77c48dacec60e6dcb0b5391d57af6a65a312a90648c0"},
+    {file = "idna-2.10.tar.gz", hash = "sha256:b307872f855b18632ce0c21c5e45be78c0ea7ae4c15c828c20788b26921eb3f6"},
+]
+python-dateutil = [
+    {file = "python-dateutil-2.8.1.tar.gz", hash = "sha256:73ebfe9dbf22e832286dafa60473e4cd239f8592f699aa5adaf10050e6e1823c"},
+    {file = "python_dateutil-2.8.1-py2.py3-none-any.whl", hash = "sha256:75bb3f31ea686f1197762692a9ee6a7550b59fc6ca3a1f4b5d7e32fb98e2da2a"},
+]
+requests = [
+    {file = "requests-2.25.1-py2.py3-none-any.whl", hash = "sha256:c210084e36a42ae6b9219e00e48287def368a26d03a048ddad7bfee44f75871e"},
+    {file = "requests-2.25.1.tar.gz", hash = "sha256:27973dd4a904a4f13b263a19c866c13b92a39ed1c964655f025f3f8d3d75b804"},
+]
+six = [
+    {file = "six-1.15.0-py2.py3-none-any.whl", hash = "sha256:8b74bedcbbbaca38ff6d7491d76f2b06b3592611af620f8426e82dddb04a5ced"},
+    {file = "six-1.15.0.tar.gz", hash = "sha256:30639c035cdb23534cd4aa2dd52c3bf48f06e5f4a941509c8bafd8ce11080259"},
+]
+urllib3 = [
+    {file = "urllib3-1.26.4-py2.py3-none-any.whl", hash = "sha256:2f4da4594db7e1e110a944bb1b551fdf4e6c136ad42e4234131391e21eb5b0df"},
+    {file = "urllib3-1.26.4.tar.gz", hash = "sha256:e7b021f7241115872f92f43c6508082facffbd1c048e3c6e2bb9c2a157e28937"},
+]
diff --git a/client/pyproject.toml b/client/pyproject.toml
new file mode 100644
index 0000000..89efa19
--- /dev/null
+++ b/client/pyproject.toml
@@ -0,0 +1,36 @@
+[tool.poetry]
+name = "pypssl"
+version = "2.2"
+description = "Python API for PSSL."
+authors = ["Raphaël Vinot <raphael.vinot@circl.lu>"]
+license = "GPLv3"
+
+repository = "https://github.com/adulau/crl-monitor/tree/master/client"
+
+readme = "README.md"
+
+classifiers = [
+    'License :: OSI Approved :: GNU General Public License v3 (GPLv3)',
+    'Development Status :: 5 - Production/Stable',
+    'Environment :: Console',
+    'Intended Audience :: Science/Research',
+    'Intended Audience :: Telecommunications Industry',
+    'Programming Language :: Python :: 2.7',
+    'Programming Language :: Python :: 3',
+    'Topic :: Security',
+    'Topic :: Internet',
+]
+
+[tool.poetry.scripts]
+pssl = "bin.pssl:main"
+
+[tool.poetry.dependencies]
+python = "^3.6"
+requests = "^2.25.1"
+python-dateutil = "^2.8.1"
+
+[tool.poetry.dev-dependencies]
+
+[build-system]
+requires = ["poetry-core>=1.0.0"]
+build-backend = "poetry.core.masonry.api"