diff --git a/.gitignore b/.gitignore
index bd63e04..097a49a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@
 /secrets/
 /private_deps/
 /data/
+/config/
 
 # Python
 __pycache__/
diff --git a/ruff.toml b/ruff.toml
new file mode 100644
index 0000000..84f683e
--- /dev/null
+++ b/ruff.toml
@@ -0,0 +1,69 @@
+#[tool.ruff]
+lint.select = [ 'ALL' ]
+lint.ignore = [
+    'ANN', # Type annotations (lots of work.)
+    'FBT', # Boolean trap is bullshit.
+    'C90', 'PLR0911',  'PLR0915', 'PLR0913', # Code complexity measures are bullshit.
+    'Q003', 'D205', # Format conflict
+
+    'TCH', # Microoptimization at the cost of readability
+
+    'D100', 'D101', 'D102', 'D103', 'D104', 'D105', 'D106', 'D107', 'D300', 'D401', # Missing docstrings (lots of work)
+    'TD002', 'TD003', 'TD004', 'FIX', # Who cares about TODO standards?
+    "E501", 'PLR0912', 'PTH123', 'F405', 'E402', 'PLW0603',
+
+    'SIM102',
+
+    'TRY002', 'TRY003',
+]
+
+# Autofix
+lint.fixable = [
+    'SIM', 'C', 'Q', 'D',
+    'UP035', 'UP004', 'UP032', 'UP006', 'UP007', 'I001',
+    'F401', 'COM812', 'B011', 'PLR1722', 'PLR0402', 'S101',
+]
+lint.unfixable = ['SIM102', 'SIM114']
+
+# Exclude a variety of commonly ignored directories.
+exclude = [
+    ".bzr",
+    ".direnv",
+    ".eggs",
+    ".git",
+    ".hg",
+    ".mypy_cache",
+    ".nox",
+    ".pants.d",
+    ".pytype",
+    ".ruff_cache",
+    ".svn",
+    ".tox",
+    ".venv",
+    "__pypackages__",
+    "_build",
+    "buck-out",
+    "build",
+    "dist",
+    "node_modules",
+    "venv",
+]
+
+# Same as Black.
+line-length = 88
+
+# Allow unused variables when underscore-prefixed.
+lint.dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
+
+# Assume Python 3.10.
+target-version = "py310"
+
+[lint.flake8-quotes]
+inline-quotes = "single"
+multiline-quotes = "double"
+docstring-quotes = "double"
+
+[format]
+quote-style = "single"
+indent-style = "space"
+docstring-code-format = true
diff --git a/setup.py b/setup.py
index 1350675..e77c2db 100644
--- a/setup.py
+++ b/setup.py
@@ -15,7 +15,6 @@ PACKAGE_NAME = 'fin_depo'
 with open('README.md') as f:
     readme = f.read()
 
-
 def parse_version_file(text: str) -> str:
     match = re.match(r'^__version__\s*=\s*(["\'])([\d\.]+)\1$', text)
     if match is None:
@@ -23,11 +22,9 @@ def parse_version_file(text: str) -> str:
         raise Exception(msg)
     return match.group(2)
 
-
 with open(PACKAGE_NAME + '/_version.py') as f:
     version = parse_version_file(f.read())
 
-
 def parse_requirements(text: str) -> list[str]:
     return text.strip().split('\n')
 
@@ -49,6 +46,7 @@ def determine_short_description(readme: str) -> str:
 
 REQUIREMENTS_MAIN = """
 enforce-typing
+fin-defs @ git+https://gitfub.space:Jmaa/fin-defs.git
 """
 
 REQUIREMENTS_TEST = """