diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1b565ee7..fef8e427 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,14 +47,38 @@ jobs:
         env:
           UV_PYTHON: ${{ matrix.python-version }}
 
+  crosshair:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+          fetch-depth: 0
+          fetch-tags: true
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v10.1.0
+        with:
+          enable-cache: true
+          cache-dependency-glob: '**/pyproject.toml'
+
+      - name: Run property tests with CrossHair
+        run: |
+          uv run --group=dev --group=crosshair pytest -vvv tests/test_vws_auth_tools.py
+        env:
+          HYPOTHESIS_BACKEND: crosshair
+          UV_PYTHON: '3.14'
+
   completion-ci:
-    needs: build
+    needs: [build, crosshair]
     runs-on: ubuntu-latest
     if: always()  # Run even if one matrix job fails
     steps:
       - name: Check matrix job status
         run: |-
-          if ! ${{ needs.build.result == 'success' }}; then
+          if ! ${{ needs.build.result == 'success' && needs.crosshair.result == 'success' }}; then
             echo "One or more matrix jobs failed"
             exit 1
           fi
diff --git a/pyproject.toml b/pyproject.toml
index d2da6e06..67e04af1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -87,6 +87,10 @@ dev = [
     "yamlfix==1.19.1",
     "zizmor==1.30.1",
 ]
+crosshair = [
+    "crosshair-tool==0.0.110",
+    "hypothesis-crosshair==0.0.30",
+]
 release = [ "check-wheel-contents==0.6.3", "towncrier==26.9.0" ]
 
 [tool.setuptools]
diff --git a/tests/test_vws_auth_tools.py b/tests/test_vws_auth_tools.py
index c12fbe81..134aeb47 100644
--- a/tests/test_vws_auth_tools.py
+++ b/tests/test_vws_auth_tools.py
@@ -3,15 +3,21 @@
 import base64
 import datetime
 import hashlib
+import os
 from zoneinfo import ZoneInfo
 
 import pytest
 from freezegun import freeze_time
-from hypothesis import given
+from hypothesis import given, settings
 from hypothesis import strategies as st
 
 import vws_auth_tools
 
+_HYPOTHESIS_BACKEND = os.environ.get(
+    key="HYPOTHESIS_BACKEND",
+    default="hypothesis",
+)
+
 
 def test_rfc_1123_date() -> None:
     """The date is returned in the format described in the VWS
@@ -103,6 +109,7 @@ def test_authorization_header_empty_content(
     assert result == "VWS my_access_key:XXvKyRyMkwS8/1P1WLQ0duqNpKs="
 
 
+@settings(backend=_HYPOTHESIS_BACKEND, deadline=None)
 @given(
     access_key=st.text(),
     secret_key=st.text(),
@@ -170,6 +177,7 @@ def test_basic_authorization_header_empty_credentials() -> None:
     assert result == "Basic Og=="
 
 
+@settings(backend=_HYPOTHESIS_BACKEND)
 @given(client_id=st.text(), client_secret=st.text())
 def test_basic_authorization_header_encodes_utf_8(
     *,
@@ -191,6 +199,7 @@ def test_basic_authorization_header_encodes_utf_8(
     assert decoded_credentials == f"{client_id}:{client_secret}"
 
 
+@settings(backend=_HYPOTHESIS_BACKEND)
 @given(access_token=st.text())
 def test_bearer_authorization_header(access_token: str) -> None:
     """The Bearer Authorization header includes the given access token."""
@@ -201,6 +210,7 @@ def test_bearer_authorization_header(access_token: str) -> None:
     assert result == f"Bearer {access_token}"
 
 
+@settings(backend=_HYPOTHESIS_BACKEND)
 @given(content=st.text())
 def test_authorization_header_encodes_unicode_content(content: str) -> None:
     """Unicode content is equivalent to its UTF-8 encoded bytes."""