diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000000000000000000000000000000000000..e8f8f2de24be8f313e53416d31ebdfc391418d93
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,2 @@
+[build-system]
+requires = ["cython==0.29.21", "numpy==1.19.1"]
diff --git a/requirements.txt b/requirements.txt
index 37722e730835f2a7e3b20787b438e80234823b4d..04bca6f52b15f7b480e816dfbe23a0b2b326385b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,6 @@ git+file:///gpfs/exfel/sw/calsoft/git/nbparameterise@0.3
 git+file:///gpfs/exfel/sw/calsoft/git/pyDetLib@2.5.3-2.7.0#subdirectory=lib
 astcheck == 0.2.5
 astsearch == 0.1.3
-Cython == 0.29.21
 dill == 0.3.0
 extra_data == 1.2.0
 extra_geom == 1.0.0
@@ -26,12 +25,12 @@ lxml == 4.5.0
 metadata_client == 3.0.5
 nbconvert == 5.6.1
 nbformat == 5.0.7
-numpy == 1.19.1
 prettytable == 0.7.2
 pypandoc == 1.4
 python-dateutil == 2.8.1
 pyyaml == 5.3
 pyzmq == 19.0.0
+requests==2.22.0
 scikit-learn == 0.22.2.post1
 sharedmem == 0.3.8
 sphinx == 1.8.5