diff --git a/example/.appenv/current b/example/.appenv/current
new file mode 120000
index 0000000..cfb020b
--- /dev/null
+++ b/example/.appenv/current
@@ -0,0 +1 @@
+1060a47a
\ No newline at end of file
diff --git a/example/requirements.txt b/example/requirements.txt
index 50242ed..5cfc7f9 100644
--- a/example/requirements.txt
+++ b/example/requirements.txt
@@ -1,3 +1,5 @@
 # appenv-requirements-hash: 23726ae5a1e34c3fd5735728c69f2c436b6801d9ac7df6e3d0d5eb7d03fc2a0d
-ducker==2.0.1
-setuptools==65.5.0
+ducker==2.0.1 \
+    --hash=sha256:159b84ee1103e495bbf89a69922f64f98e73f92ee76acea53a207cd45fc80ac9 \
+    --hash=sha256:50131934a2cd8aa62af8ff5e114463c7639c1fd8bb1a0c70102a351a64afe40a
+    # via -r requirements.in
diff --git a/src/appenv.py b/src/appenv.py
index 4533a36..7ddf380 100755
--- a/src/appenv.py
+++ b/src/appenv.py
@@ -62,6 +62,14 @@ def pip(path, c, **kwargs):
     return python(path, ["-m", "pip"] + c, **kwargs)
 
 
+def pip_compile(use_uv, path, c, **kwargs):
+    if use_uv:
+        return cmd([os.path.join(path, "bin/uv"), "pip", "compile"] + c,
+                   **kwargs)
+    else:
+        return cmd([os.path.join(path, "bin/pip-compile")] + c, **kwargs)
+
+
 def get(host, path, f):
     conn = http.client.HTTPSConnection(host)
     conn.request("GET", path)
@@ -141,6 +149,19 @@ def ensure_venv(target):
     python(target, ["-m", "ensurepip", "--default-pip"])
     pip(target, ["install", "--upgrade", "pip"])
 
+    # try to install uv
+    print("Ensuring uv ...")
+    uses_uv_pip_compile = False
+    try:
+        pip(target, ["install", "uv"])
+        uses_uv_pip_compile = True
+    except ValueError:
+        print("uv not available, falling back to pip-compile")
+        # pip-compile is not available in the venv, so we need to install it
+        # in the system python
+        cmd(["pip", "install", "pip-tools"])
+    return uses_uv_pip_compile
+
 
 def parse_preferences():
     preferences = None
@@ -520,59 +541,25 @@ def update_lockfile(self, args=None, remaining=None):
         tmpdir = os.path.join(self.appenv_dir, "updatelock")
         if os.path.exists(tmpdir):
             cmd(["rm", "-rf", tmpdir])
-        ensure_venv(tmpdir)
-        print("Installing packages ...")
-        pip(tmpdir, ["install", "-r", "requirements.in"])
-
-        extra_specs = []
-        result = pip(
-            tmpdir, ["freeze", "--all", "--exclude", "pip"],
-            merge_stderr=False).decode('ascii')
-        # They changed this behaviour in https://github.com/pypa/pip/pull/12032
-        pinned_versions = {}
-        for line in result.splitlines():
-            if line.strip().startswith('-e '):
-                # We'd like to pick up the original -e statement here.
-                continue
-            parsed_requirement = parse_requirement_string(line)
-            pinned_versions[parsed_requirement.name] = parsed_requirement
-        requested_versions = {}
-        with open('requirements.in') as f:
-            for line in f.readlines():
-                if line.strip().startswith('-e '):
-                    extra_specs.append(line.strip())
-                    continue
-                if line.strip().startswith('--'):
-                    extra_specs.append(line.strip())
-                    continue
-
-                # filter comments, in particular # appenv-python-preferences
-                if line.strip().startswith('#'):
-                    continue
-                parsed_requirement = parse_requirement_string(line)
-                requested_versions[
-                    parsed_requirement.name] = parsed_requirement
-
-        final_versions = {}
-        for spec in requested_versions.values():
-            # Pick versions with URLs to ensure we don't get the screwed up
-            # results from pip freeze.
-            if spec.url:
-                final_versions[spec.name] = spec
-        for spec in pinned_versions.values():
-            # Ignore versions we already picked
-            if spec.name in final_versions:
-                continue
-            final_versions[spec.name] = spec
-        lines = [str(spec) for spec in final_versions.values()]
-        lines.extend(extra_specs)
-        lines.sort()
-        with open(os.path.join(self.base, "requirements.txt"), "w") as f:
-            f.write('# appenv-requirements-hash: {}\n'.format(
-                self._hash_requirements()))
-            f.write('\n'.join(lines))
-            f.write('\n')
-        cmd(["rm", "-rf", tmpdir])
+        has_uv = ensure_venv(tmpdir)
+        # print("Installing packages ...")
+        # use uv pip compile or pip-compile to generate the requirements.txt
+
+        requirements_out = pip_compile(
+            has_uv,
+            tmpdir, [
+                "requirements.in", "--generate-hashes", "--no-header",
+                "--upgrade"],
+            merge_stderr=False)
+
+        requirements_out = requirements_out.decode("utf-8", "replace")
+        # prepend appenv-requirements-hash
+        requirements_hash = self._hash_requirements()
+        requirements_out = (
+            "# appenv-requirements-hash: {}\n".format(requirements_hash) +
+            requirements_out)
+        with open("requirements.txt", "w") as f:
+            f.write(requirements_out)
 
 
 def main():