diff --git a/poetry.lock b/poetry.lock
index bfeffbb..04d22f4 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -49,6 +49,23 @@ Flask = "*"
 WTForms = "*"
 itsdangerous = "*"
 
+[[package]]
+category = "dev"
+description = "WSGI HTTP Server for UNIX"
+name = "gunicorn"
+optional = false
+python-versions = ">=3.4"
+version = "20.0.4"
+
+[package.dependencies]
+setuptools = ">=3.0"
+
+[package.extras]
+eventlet = ["eventlet (>=0.9.7)"]
+gevent = ["gevent (>=0.13)"]
+setproctitle = ["setproctitle"]
+tornado = ["tornado (>=0.2)"]
+
 [[package]]
 category = "main"
 description = "Various helpers to pass data to untrusted environments and back."
@@ -148,7 +165,7 @@ ipaddress = ["ipaddress"]
 locale = ["Babel (>=1.3)"]
 
 [metadata]
-content-hash = "4ecee2e19e0576a331bb8c4e9f0de82f74a31d41c5daafed8dce5eb73b541281"
+content-hash = "5a3b077899ce6bd8f1a70c4fc48784486bb1373081d94c5b772191e7edb2788c"
 lock-version = "1.0"
 python-versions = "^3.8"
 
@@ -169,6 +186,10 @@ flask-wtf = [
     {file = "Flask-WTF-0.14.3.tar.gz", hash = "sha256:d417e3a0008b5ba583da1763e4db0f55a1269d9dd91dcc3eb3c026d3c5dbd720"},
     {file = "Flask_WTF-0.14.3-py2.py3-none-any.whl", hash = "sha256:57b3faf6fe5d6168bda0c36b0df1d05770f8e205e18332d0376ddb954d17aef2"},
 ]
+gunicorn = [
+    {file = "gunicorn-20.0.4-py2.py3-none-any.whl", hash = "sha256:cd4a810dd51bf497552cf3f863b575dabd73d6ad6a91075b65936b151cbf4f9c"},
+    {file = "gunicorn-20.0.4.tar.gz", hash = "sha256:1904bb2b8a43658807108d59c3f3d56c2b6121a701161de0ddf9ad140073c626"},
+]
 itsdangerous = [
     {file = "itsdangerous-1.1.0-py2.py3-none-any.whl", hash = "sha256:b12271b2047cb23eeb98c8b5622e2e5c5e9abd9784a153e9d8ef9cb4dd09d749"},
     {file = "itsdangerous-1.1.0.tar.gz", hash = "sha256:321b033d07f2a4136d3ec762eac9f16a10ccd60f53c0c91af90217ace7ba1f19"},
diff --git a/pyproject.toml b/pyproject.toml
index 47dafe8..3471c57 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,6 +12,7 @@ flask_wtf = "^0.14.3"
 
 [tool.poetry.dev-dependencies]
 mypy = "^0.800"
+gunicorn = "^20.0.4"
 
 [tool.poetry.scripts]
 redstring-check = "redstring.parser:main"