diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 060763ba2..e4ec0a345 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -42,6 +42,10 @@ jobs:
         git clone --depth 1 https://github.com/rcsb/mmtf-cpp.git
         cp -R mmtf-cpp/include/mmtf* include/
 
+    - name: Pip install python-build
+      run: |
+        pip install build
+
     - name: Build
       run: |
         pip install -v --config-settings testing=True .
diff --git a/pyproject.toml b/pyproject.toml
index 81e4ff69e..9d6698c0d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,14 +14,14 @@ authors = [
   {name = "Schrodinger", email = "pymol-users@lists.sourceforge.net"},
 ]
 dependencies = [
-  "numpy>=1.26.4",
+  "numpy>=1.26.4,<2",
 ]
 
 [build-system]
 build-backend = "backend"
 backend-path = ["_custom_build"]
 requires = [
-  "numpy>=1.26.4",
+  "numpy>=1.26.4,<2",
   "setuptools>=69.2.0",
 ]