diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a2ccc57..17b7cdb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -45,7 +45,7 @@ jobs:
       env:
         DUST_DIR: ${{github.workspace}}/data/
       run: |
-        python setup.py develop
+        pip install -ve .
     - name: Test package
       env:
         DUST_DIR: ${{github.workspace}}/data/
diff --git a/mwdust/util/healpix.py b/mwdust/util/healpix.py
index 896a3d1..5c83619 100644
--- a/mwdust/util/healpix.py
+++ b/mwdust/util/healpix.py
@@ -3,9 +3,8 @@
 import ctypes
 import ctypes.util
 from numpy.ctypeslib import ndpointer
-import os
 import numpy as np
-
+from pathlib import Path
 
 # healpy number to represent bad numbers
 UNSEEN = -1.6375e+30
@@ -17,9 +16,15 @@
 if _libname:
     _lib = ctypes.CDLL(_libname)
 if _lib is None:
-    for path in sys.path:
+    # Add top-level mwdust repository directory for pip install (-e) .,
+    # just becomes site-packages for regular install
+    paths = sys.path
+    paths.append(str(Path(__file__).parent.parent.parent.absolute()))
+    for path in [Path(p) for p in paths]:
+        if not path.is_dir():
+            continue
         try:
-            _lib = ctypes.CDLL(os.path.join(path, "healpix_c%s" % _ext_suffix))
+            _lib = ctypes.CDLL(str(path / f"healpix_c{_ext_suffix}"))
         except OSError:
             _lib = None
         else:
diff --git a/mwdust/util/read_SFD.py b/mwdust/util/read_SFD.py
index e116a1a..5523bc5 100644
--- a/mwdust/util/read_SFD.py
+++ b/mwdust/util/read_SFD.py
@@ -4,6 +4,7 @@
 import ctypes.util
 from numpy.ctypeslib import ndpointer
 import os, os.path
+from pathlib import Path
 import numpy
 import platform
 import tqdm
@@ -21,9 +22,15 @@
 if _libname:
     _lib = ctypes.CDLL(_libname)
 if _lib is None:
-    for path in sys.path:
+    # Add top-level mwdust repository directory for pip install (-e) .,
+    # just becomes site-packages for regular install
+    paths = sys.path
+    paths.append(str(Path(__file__).parent.parent.parent.absolute()))
+    for path in [Path(p) for p in paths]:
+        if not path.is_dir():
+            continue
         try:
-            _lib = ctypes.CDLL(os.path.join(path,'sfd_c%s' % _ext_suffix))
+            _lib = ctypes.CDLL(str(path / f"sfd_c{_ext_suffix}"))
         except OSError:
             _lib = None
         else:
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..fed528d
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"