diff --git a/pyproject.toml b/pyproject.toml
index dbb4d17..e667d66 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,7 @@
+[build-system]
+requires = ["setuptools>=21.0.0"]
+build-backend = "setuptools.build_meta"
+
 # pytest options
 [tool.pytest.ini_options]
 minversion = "9.0"
diff --git a/requirements.lint.txt b/requirements.lint.txt
index 058441c..4715796 100644
--- a/requirements.lint.txt
+++ b/requirements.lint.txt
@@ -3,6 +3,7 @@
 black~=26.3.1
 mypy~=1.15.0
 mypy-extensions~=1.0.0
+responses~=0.25.6
 ruff~=0.9.0
 types-requests~=2.33.0
 types-urllib3~=1.26.25.14
diff --git a/requirements.txt b/requirements.txt
index c2586a5..3642744 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,8 +1,6 @@
-setuptools >= 21.0.0
 urllib3 >= 1.15.1
 requests >= 2.33.0
 wasmtime ~= 30.0.0
 protobuf >= 4.23.3
 openfeature-sdk ~= 0.8
 launchdarkly-eventsource >= 1.2.1
-responses >= 0.23.1
\ No newline at end of file