diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9811dc7da..421053b1b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -152,82 +152,96 @@ jobs:
         - ubuntu-latest
         - macos-latest
     steps:
-      - name: Check out source
+      - name: 📥 Check out source
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Set up Python
+      - name: 🐍 Set up Python
         uses: actions/setup-python@v5
         id: pyinstall
         with:
           python-version: ${{matrix.python}}
           cache: 'pip'
 
-      - name: Install build tools
+      - name: 🛠️ Install build tools
         run: |
-          "$PYTHON" -m pip install -U 'uv>=0.1.15'
+          "$PYTHON" -m pip install -U pdm
         env:
           PYTHON: ${{ steps.pyinstall.outputs.python-path }}
 
-      - name: Set up Python deps
-        run: uv pip install --python "$PYTHON" -e '.[test]'
-        env:
-          PYTHON: ${{ steps.pyinstall.outputs.python-path }}
+      - name: 📦 Set up Python deps
+        run: |
+          pdm venv create "${{matrix.python}}"
+          pdm lock -S no_cross_platform
+          pdm install -dG test -v
 
-      - name: Inspect environment
+      - name: 🔍 Inspect environment
         run: |
-          pip list
+          pdm info
+          pdm list
 
-      - name: Run tests
+      - name: 🏃🏽‍♀️‍➡️ Run tests
         run: |
-          "$PYTHON" -m pytest --cov=lenskit --cov-report=xml --log-file=test.log
-        env:
-          PYTHON: ${{ steps.pyinstall.outputs.python-path }}
+          pdm run python -m pytest --cov=lenskit --cov-report=xml --log-file=test.log
 
-      - name: Process test results
-        uses: lenskit/lkbuild/actions/save-test-results@main
+      - name: 🥼 Aggreagate coverage data
+        run: pdm run coverage xml
+
+      - name: 🪵 Upload logs
+        uses: actions/upload-artifact@v3
         with:
-          artifact-name: test-vanilla-${{matrix.platform}}-py${{matrix.python}}
+          name: test-vanilla-${{matrix.platform}}-py${{matrix.python}}
+          path: |
+            test*.log
+            coverage.xml
 
   mindep:
     name: Minimal Supported Dependencies
     runs-on: ubuntu-latest
     steps:
-      - name: Check out source
+      - name: 📥 Check out source
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Set up Python
+      - name: 🐍 Set up Python
         uses: actions/setup-python@v5
         id: pyinstall
         with:
           python-version: '3.10'
 
-      - name: Install build tools
+      - name: 🛠️ Install build tools
         run: |
-          "$PYTHON" -m pip install -U 'uv>=0.1.15'
+          "$PYTHON" -m pip install -U pdm
         env:
           PYTHON: ${{ steps.pyinstall.outputs.python-path }}
 
-      - name: Set up Python deps
-        run: uv pip install --python "$PYTHON" --resolution=lowest-direct -e '.[test]'
-        env:
-          PYTHON: ${{ steps.pyinstall.outputs.python-path }}
+      - name: 📦 Set up Python deps
+        run: |
+          pdm venv create 3.10
+          pdm lock -S direct_minimal_versions -S no_cross_platform
+          pdm install -dG test
 
-      - name: Inspect environment
+      - name: 🔍 Inspect environment
         run: |
-          pip list
+          pdm info
+          pdm list
 
-      - name: Run tests
+      - name: 🏃🏽‍♀️‍➡️ Run tests
         run: |
-          python -m pytest --cov=lenskit --cov-report=xml --log-file test.log
+          pdm run python -m pytest --cov=lenskit --cov-report=xml --log-file=test.log
 
-      - name: Process Test Results
-        uses: lenskit/lkbuild/actions/save-test-results@main
+      - name: 🥼 Aggreagate coverage data
+        run: pdm run coverage xml
+
+      - name: 🪵 Upload logs
+        uses: actions/upload-artifact@v3
         with:
-          artifact-name: test-mindeps
+          name: test-vanilla-min-deps
+          path: |
+            test*.log
+            coverage.xml
 
   results:
     name: Test Suite Results
diff --git a/.gitignore b/.gitignore
index 4e8519b84..ceb99646f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -42,6 +42,13 @@ lenskit/**/*.c
 conda-lock.yml
 *.lock
 *.lock.yml
+pdm.lock
+.pdm-build/
+.pdm-plugins/
+
+# ignore local pdm config
+.pdm-python
+pdm.toml
 
 # Editor and OS cruft
 .DS_Store
diff --git a/pyproject.toml b/pyproject.toml
index 8094c46f2..b449de965 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [build-system]
-requires = ["setuptools>=64", "setuptools_scm>=8"]
-build-backend = "setuptools.build_meta"
+requires = ["pdm-backend"]
+build-backend = "pdm.backend"
 
 [project]
 name = "lenskit"
@@ -23,7 +23,7 @@ license = { file = "LICENSE.md" }
 dynamic = ["version"]
 dependencies = [
   "pandas >=1.5, <3",
-  "numpy >= 1.23",
+  "numpy >= 1.23,<2",
   "scipy >= 1.9.0",
   "numba >= 0.56, < 0.59",
   "torch ~=2.1",            # p2c: -s pytorch==2.*
@@ -36,6 +36,32 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
+sklearn = ["scikit-learn >= 1.1"]
+
+[project.urls]
+homepage = "https://lenskit.org"
+documentation = "https://lkpy.lenskit.org"
+source = "https://github.com/lenskit/lkpy"
+
+# configure build tools
+[tool.pdm]
+distribution = true
+
+[tool.pdm.version]
+source = "scm"
+
+[tool.pdm.build]
+includes = [
+  "lenskit",
+]
+source-includes = [
+  "CITATION.cff",
+  "tests/*",
+  "docs/*",
+  "conftest.py",
+]
+
+[tool.pdm.dev-dependencies]
 dev = [
   "setuptools>=64",
   "setuptools_scm>=8",
@@ -71,32 +97,36 @@ demo = [
   "nbformat >=5.2",
   "ipython >= 7",
 ]
-sklearn = ["scikit-learn >= 1.1"]
 
-[project.urls]
-homepage = "https://lenskit.org"
-documentation = "https://lkpy.lenskit.org"
-source = "https://github.com/lenskit/lkpy"
-
-# configure build tools
-[tool.flit.sdist]
-include = ["tests/*"]
-exclude = [
-  ".github",
-  "*.ipynb",
-  "docs",
-  "data",
-  "examples",
-  "build-tools",
-  "lkbuild",
-  "tasks.py",
+[tool.pdm.conda]
+solver = "libmamba"
+as-default-manager = true
+# auto-excludes = true
+runner = "conda"
+batched-commands = true
+channels = [
+  "conda-forge",
+  "pytorch",
+  "nodefaults",
+]
+dependencies = [
+  "tbb",
+]
+excludes = [
+  "manylog",
+  "progress-api",
+  "seedbank",
+  "unbeheader",
 ]
 
-[tool.setuptools]
-packages = ["lenskit"]
+[tool.pdm.conda.pypi-mapping]
+download-dir = "/tmp"
+
+[tool.pdm.conda.dev-dependencies]
+dev = [
+  "just==1.*",
+]
 
-[tool.setuptools_scm]
-version_scheme = "release-branch-semver"
 
 # settings for generating conda environments for dev & CI, when needed
 [tool.pyproject2conda]