diff --git a/.flake8 b/.flake8
new file mode 100644
index 00000000..cf84c825
--- /dev/null
+++ b/.flake8
@@ -0,0 +1,236 @@
+[flake8]
+
+# Don't even try to analyze these:
+extend-exclude =
+  # No need to traverse egg info dir
+  *.egg-info,
+  # GitHub configs
+  .github,
+  # Cache files of MyPy
+  .mypy_cache,
+  # Cache files of pytest
+  .pytest_cache,
+  # Temp dir of pytest-testmon
+  .tmontmp,
+  # Occasional virtualenv dir
+  .venv,
+  # VS Code
+  .vscode,
+  # Temporary build dir
+  build,
+  # This contains sdists and wheels of proxy.py that we don't want to check
+  dist,
+  # Occasional virtualenv dir
+  env,
+  # Metadata of `pip wheel` cmd is autogenerated
+  pip-wheel-metadata,
+
+# IMPORTANT: avoid using ignore option, always use extend-ignore instead
+# Completely and unconditionally ignore the following errors:
+extend-ignore =
+  I  # flake8-isort is drunk + we have isort integrated into pre-commit
+  B009    # FIXME: `getattr()` called with a constant arg
+  C812    # FIXME: missing trailing comma
+  C819    # FIXME: inline trailing comma
+  D101
+  D102
+  D103
+  D105
+  D106
+  D107
+  D203
+  D205
+  D208
+  D209
+  D212
+  D213
+  D300
+  D400
+  D401
+  D402
+  D403
+  D404
+  D405
+  D407
+  D412
+  D413
+  D415
+  DAR101  # FIXME: undocumented docstring param
+  DAR201  # FIXME: no "returns" in docstring
+  DAR301  # FIXME: no "yields" in docstring
+  DAR401  # FIXME: no "raises" in docstring
+  E800    # FIXME: commented out code
+  N400    # FIXME: escaping with backslash at EOL
+  N801    # FIXME: class name should use ProudCamelCase
+  N802    # FIXME: func name should be lowercase
+  N816    # FIXME: mixed case var name
+  P101    # FIXME: format string with unindexed params
+  PT009   # FIXME: pytest encourages use of `assert`
+  PT018   # FIXME: use multiple `assert`s instead of one complex
+  Q000    # FIXME: inconsistent double quotes use when single ones are needed
+  Q001    # FIXME: use double quotes in multiline strings
+  Q002    # FIXME: use double quote docstrings
+  Q003    # FIXME: avoid escaping in-string quotes
+  RST201  # FIXME: missing trailing blank line in docstring
+  RST203  # FIXME: no trailing blank line in docstring
+  RST301  # FIXME: unexpected indent in docstring
+  S101    # FIXME: assertions are thrown away in optimized mode, needs audit
+  S104    # FIXME: bind-all interface listen
+  S105    # FIXME: hardcoded password?
+  S303    # FIXME: insecure hash func
+  S311    # FIXME: `random` needs auditing
+  S404    # FIXME: `subprocess` use needs auditing
+  S603    # FIXME: audit untrusted `subprocess.Popen` input
+  S607    # FIXME: running subprocess with a non-absolute executable path
+  WPS100  # FIXME: unhelpful module name
+  WPS102  # FIXME: incorrect module name pattern
+  WPS110  # FIXME: unhelpful var name
+  WPS111  # FIXME: too short var name
+  WPS114  # FIXME: underscored numbers in var name
+  WPS115  # FIXME: uppercase class attr
+  WPS118  # FIXME: long func name
+  WPS120  # FIXME: regular name w/ trailing underscore
+  WPS121  # FIXME: unused var used 0_O
+  WPS122  # FIXME: unused var definition 0_O
+  WPS201  # FIXME: too many imports
+  WPS202  # FIXME: too many mod members
+  WPS203  # FIXME: too many mod imported names
+  WPS204  # FIXME: too much copy-paste
+  WPS210  # FIXME: too many local vars
+  WPS211  # FIXME: too many "__init__()" args
+  WPS212  # FIXME: too many "return"s
+  WPS213  # FIXME: too many expressions
+  WPS214  # FIXME: too many methods
+  WPS216  # FIXME: too many decorators
+  WPS219  # FIXME: deep object access is unreadable
+  WPS220  # FIXME: deep code nesting
+  WPS221  # FIXME: too big inline complexity / tested instructions
+  WPS222  # FIXME: too much logic in condition
+  WPS223  # FIXME: the code is too branchy
+  WPS225  # FIXME: too many "except"s
+  WPS226  # FIXME: magic string constant used too much, put it in a var
+  WPS229  # FIXME: try/except should wrap exactly one instruction
+  WPS230  # FIXME: too many public instance attrs
+  WPS231  # FIXME: insane complexity/code nesting in a function
+  WPS232  # FIXME: module is too complex
+  WPS234  # FIXME: annotation is too complex
+  WPS235  # FIXME: too many imported names from a single module
+  WPS237  # FIXME: too complex f-string
+  WPS300  # local folder imports are needed
+  WPS301  # FIXME: dotted import
+  WPS305  # this project is Python 3 only and so f-strings are allowed
+  WPS306  # this project is Python 3 so it doesn't need an explicit class base
+  WPS313  # FIXME: parens after keyword
+  WPS317  # enforces weird indents
+  WPS318  # enforces weird indents
+  WPS319  # FIXME: asymmetric closing bracket
+  WPS320  # FIXME: multiline func type annotation
+  WPS322  # FIXME: inline multiline str
+  WPS323  # false-positive: %-formatting in logging
+  WPS324  # FIXME: inconsistent "return" in func
+  WPS326  # doesn't allow implicit string concat
+  WPS328  # FIXME: useless `while` node
+  WPS336  # FIXME: explicit string concat
+  WPS337  # FIXME: multiline conditions
+  WPS338  # FIXME: unordered class methods
+  WPS339  # FIXME: meaningless leading zeros in number
+  WPS349  # FIXME: redundant slice
+  WPS360  # FIXME: unnecessary r-string
+  WPS361  # FIXME: inconsistent comprehension structure
+  WPS403  # FIXME: `# noqa` overuse
+  WPS407  # FIXME: mutable mod const
+  WPS408  # FIXME: duplicate logical condition
+  WPS410  # allow `__all__`
+  WPS412  # FIXME: logic in `__init__`
+  WPS414  # FIXME: consusing unpacking target
+  WPS420  # FIXME: pointless keyword like `pass`
+  WPS421  # FIXME: call to `print()`
+  WPS425  # FIXME: bool non-keyword arg
+  WPS427  # FIXME: unreachable code
+  WPS428  # FIXME: pointless statement
+  WPS430  # FIXME: nested func
+  WPS431  # FIXME: nested class
+  WPS432  # FIXME: magic number w/o assigned context/name
+  WPS433  # FIXME: nested import
+  WPS437  # FIXME: protected attr access
+  WPS440  # FIXME: block vars overlap
+  WPS441  # FIXME: control var use after block
+  WPS442  # FIXME: outer scope var shadowing
+  WPS453  # FIXME: executable file w/o shebang
+  WPS454  # FIXME: don't raise a broad exception, use a specific one
+  WPS457  # FIXME: infinite `while`
+  WPS458  # FIXME: import collision
+  WPS460  # FIXME: single element unpacking
+  WPS464  # FIXME: empty comment
+  WPS501  # FIXME: "finally" in "try" w/o "except"
+  WPS504  # FIXME: invert a negated condition
+  WPS505  # FIXME: nested "try" in "try"
+  WPS507  # FIXME: useless `len()`
+  WPS508  # FIXME: misused `not` in if-clause
+  WPS509  # FIXME: incorrect ternary nesting
+  WPS510  # FIXME: if-clause with `in` operator w/ wrong set semantics
+  WPS513  # FIXME: implicit `elif`
+  WPS515  # FIXME: implicit `open()` w/o a CM
+  WPS518  # FIXME: implicit `enumerate()` pattern
+  WPS519  # FIXME: implicit `sum()` pattern
+  WPS528  # FIXME: implicit `dict.items()` pattern
+  WPS529  # FIXME: implicit `dict.get()` pattern
+  WPS531  # FIXME: simplifiable returning `if` in func
+  WPS602  # FIXME: `@staticmethod` is usually a code smell, use module funcs
+  WPS604  # FIXME: incorrect class body node
+  WPS605  # FIXME: method w/o args
+  WPS609  # FIXME: direct call to magic method
+  WPS612  # FIXME: useless `__init__()` override
+  WPS613  # FIXME: unmatching super method access
+  WPS615  # FIXME: unpythonic setter/getter
+
+# https://wemake-python-stylegui.de/en/latest/pages/usage/formatter.html
+format = wemake
+
+# Let's not overcomplicate the code:
+#max-complexity = 10
+# FIXME: this is a lot!
+max-complexity = 19
+
+# Accessibility/large fonts and PEP8 friendly:
+#max-line-length = 79
+# Accessibility/large fonts and PEP8 unfriendly:
+#max-line-length = 100
+# Even more Accessibility/large fonts and PEP8 unfriendlier:
+max-line-length = 127
+
+# Allow certain violations in certain files:
+per-file-ignores =
+
+  # E800 reports a lot of false-positives for legit
+  # tool-related comments;
+  # WPS412 logic of an extension is in __init__.py file;
+  # FIXME: WPS201 too many imports
+  # FIXME: WPS402 too many `noqa`s
+  #proxy/__init__.py: E800, WPS201, WPS402, WPS412
+
+  # There are multiple `assert`s (S101)
+  # and subprocesses (import – S404; call – S603) in tests;
+  # also, using fixtures looks like shadowing the outer scope (WPS442);
+  # and finally it's impossible to have <= members in tests (WPS202):
+  tests/**.py: S101, S404, S603, WPS202, WPS442
+
+# wemake-python-styleguide
+show-source = true
+
+# flake8-pytest-style
+# PT001:
+pytest-fixture-no-parentheses = true
+# PT006:
+pytest-parametrize-names-type = tuple
+# PT007:
+pytest-parametrize-values-type = tuple
+pytest-parametrize-values-row-type = tuple
+
+# flake8-rst-docstrings
+rst-roles =
+    # Built-in Sphinx roles:
+    py:class,
+    py:meth,
+    # Sphinx's internal role:
+    event,