diff --git a/.flake8 b/.flake8
new file mode 100644
index 0000000000..5d0b0823f1
--- /dev/null
+++ b/.flake8
@@ -0,0 +1,4 @@
+[flake8]
+ignore = E127,E226,E301,E302,E303,E309,E402,E701,E711,E712,E731
+max_line_length = 120
+show_source = True
diff --git a/Makefile b/Makefile
index 80679afe29..6065593f19 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,6 @@ pip := pip --disable-pip-version-check
 with_local_env := $(env_bin)/honcho run -e defaults.env,local.env
 with_tests_env := $(env_bin)/honcho run -e $(test_env_files)
 py_test := $(with_tests_env) $(env_bin)/py.test
-pep8_ignore = E127,E226,E301,E302,E303,E309,E402,E701,E711,E712,E731
 
 echo:
 	@echo $($(var))
@@ -55,7 +54,7 @@ test-schema: env
 	$(with_tests_env) ./recreate-schema.sh test
 
 pyflakes: env
-	$(env_bin)/flake8 --max-line-length=120 --show-source --ignore=$(pep8_ignore) app.py liberapay tests
+	$(env_bin)/flake8 app.py liberapay tests
 
 test: test-schema pytest
 tests: test
diff --git a/tox.ini b/tox.ini
index 9856d641bd..8c4a6797ea 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,6 +5,7 @@ skipsdist = True
 [testenv]
 commands =
     honcho run -e defaults.env,tests/test.env,tests/local.env python -m pytest tests/py {posargs}
+    flake8 app.py liberapay tests
 deps =
     --requirement=requirements.txt
     --requirement=requirements_dev.txt