diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5e1e74ffa..9f8766a86 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -119,13 +119,13 @@ endif()
 
 find_program(
   VARA_FEATURE_RUN_CLANG_TIDY
-  NAMES run-clang-tidy-12.py
-        run-clang-tidy-12
+  NAMES run-clang-tidy-14.py
+        run-clang-tidy-14
         run-clang-tidy.py
         run-clang-tidy
-        clang-tidy-12
+        clang-tidy-14
         clang-tidy
-  PATHS /usr/lib/llvm/*/share/clang/ /usr/bin/
+  PATHS /usr/bin/ /usr/lib/llvm/*/share/clang/
 )
 
 add_custom_target(
diff --git a/bindings/python/tests/TEST_INPUTS/example_feature_model.xml b/bindings/python/tests/TEST_INPUTS/example_feature_model.xml
index fe7efcc28..2b5ae0aff 100644
--- a/bindings/python/tests/TEST_INPUTS/example_feature_model.xml
+++ b/bindings/python/tests/TEST_INPUTS/example_feature_model.xml
@@ -84,4 +84,13 @@
       <values>1;5;9</values>
     </configurationOption>
   </numericOptions>
+  <booleanConstraints>
+    <constraint>(A | B)</constraint>
+  </booleanConstraints>
+  <nonBooleanConstraints>
+    <constraint>(A + B)</constraint>
+  </nonBooleanConstraints>
+  <mixedConstraints>
+    <constraint req="all" exprKind="pos">((A * B) = 0)</constraint>
+  </mixedConstraints>
 </vm>
diff --git a/bindings/python/tests/constraint/test_constraint.py b/bindings/python/tests/constraint/test_constraint.py
index 025c9f553..b5b933866 100644
--- a/bindings/python/tests/constraint/test_constraint.py
+++ b/bindings/python/tests/constraint/test_constraint.py
@@ -4,6 +4,7 @@
 import unittest
 
 import vara_feature.constraint as constraint
+import vara_feature.feature_model as FM
 
 
 class TestConstraintBuilder(unittest.TestCase):
@@ -30,3 +31,34 @@ def test_full(self):
         cb.feature("D").closePar().closePar().closePar().closePar().implies()
         cb.feature("E").closePar()
         self.assertEqual("((A => (!!B => !(!C => !!D))) => E)", str(cb.build()))
+
+
+class TestConstraints(unittest.TestCase):
+    """ Test Constraints functionality. """
+
+    def test_boolean_constraints(self):
+        """ Check if we can build boolean constraints. """
+        cb = constraint.ConstraintBuilder()
+        cb.feature("A").lOr().feature("B")
+        c = FM.BooleanConstraint(cb.build())
+        self.assertEqual(str(c), "(A | B)")
+        self.assertEqual(str(c.constraint.clone()), "(A | B)")
+
+    def test_non_boolean_constraints(self):
+        """ Check if we can build non-boolean constraints. """
+        cb = constraint.ConstraintBuilder()
+        cb.feature("A").add().feature("B")
+        c = FM.NonBooleanConstraint(cb.build())
+        self.assertIsNotNone(c.constraint)
+        self.assertEqual(str(c), "(A + B)")
+        self.assertEqual(str(c.constraint.clone()), "(A + B)")
+
+    def test_mixed_constraints(self):
+        """ Check if we can build mixed constraints. """
+        cb = constraint.ConstraintBuilder()
+        cb.feature("A").multiply().feature("B").equal().constant(0)
+        c = FM.MixedConstraint(cb.build(), FM.Req.ALL, FM.ExprKind.POS)
+        self.assertEqual(c.req, FM.Req.ALL)
+        self.assertEqual(c.exprKind, FM.ExprKind.POS)
+        self.assertEqual(str(c), "((A * B) = 0)")
+        self.assertEqual(str(c.constraint.clone()), "((A * B) = 0)")
diff --git a/bindings/python/tests/feature_model/test_feature_model.py b/bindings/python/tests/feature_model/test_feature_model.py
index c584b0ef7..64957935c 100644
--- a/bindings/python/tests/feature_model/test_feature_model.py
+++ b/bindings/python/tests/feature_model/test_feature_model.py
@@ -148,6 +148,23 @@ def test_merge_models(self):
         self.assertEqual(
             test_merged.get_feature("Z").parent().name.str(), "root")
 
+    def test_boolean_constraints(self):
+        """ Check if we can access boolean constraints. """
+        *_, c = iter(self.fm.booleanConstraints)
+        self.assertEqual(str(c), "(A | B)")
+
+    def test_non_boolean_constraints(self):
+        """ Check if we can access non-boolean constraints. """
+        *_, c = iter(self.fm.nonBooleanConstraints)
+        self.assertEqual(str(c), "(A + B)")
+
+    def test_mixed_constraints(self):
+        """ Check if we can access mixed constraints. """
+        *_, c = iter(self.fm.mixedConstraints)
+        self.assertEqual(c.req, FM.Req.ALL)
+        self.assertEqual(c.exprKind, FM.ExprKind.POS)
+        self.assertEqual(str(c), "((A * B) = 0)")
+
 
 class TestFeatureModelModifications(unittest.TestCase):
     """
diff --git a/bindings/python/vara-feature/pybind_Constraint.cpp b/bindings/python/vara-feature/pybind_Constraint.cpp
index 8b240a9d0..04b50c960 100644
--- a/bindings/python/vara-feature/pybind_Constraint.cpp
+++ b/bindings/python/vara-feature/pybind_Constraint.cpp
@@ -8,7 +8,8 @@ namespace py = pybind11;
 
 void init_constraint_module_constraint(py::module &M) {
   py::class_<vf::Constraint>(M, "Constraint")
-      .def("__str__", &vf::Constraint::toString);
+      .def("__str__", &vf::Constraint::toString)
+      .def("clone", &vf::Constraint::clone);
 }
 
 void init_constraint_module_constraint_builder(py::module &M) {
diff --git a/bindings/python/vara-feature/pybind_FeatureModel.cpp b/bindings/python/vara-feature/pybind_FeatureModel.cpp
index d1fa4f3a1..c279a25b0 100644
--- a/bindings/python/vara-feature/pybind_FeatureModel.cpp
+++ b/bindings/python/vara-feature/pybind_FeatureModel.cpp
@@ -13,6 +13,46 @@ namespace vf = vara::feature;
 namespace py = pybind11;
 
 void init_feature_model_module(py::module &M) {
+  py::class_<vf::FeatureModel::BooleanConstraint>(M, "BooleanConstraint")
+      .def(py::init([](vf::Constraint &C) {
+        return std::make_unique<vf::FeatureModel::BooleanConstraint>(C.clone());
+      }))
+      .def("__str__", &vf::FeatureModel::BooleanConstraint::toString)
+      .def_property_readonly("constraint",
+                             &vf::FeatureModel::BooleanConstraint::constraint,
+                             R"pbdoc(Get underlying constraint.)pbdoc");
+
+  py::class_<vf::FeatureModel::NonBooleanConstraint>(M, "NonBooleanConstraint")
+      .def(py::init([](vf::Constraint &C) {
+        return std::make_unique<vf::FeatureModel::NonBooleanConstraint>(
+            C.clone());
+      }))
+      .def("__str__", &vf::FeatureModel::NonBooleanConstraint::toString)
+      .def_property_readonly(
+          "constraint", &vf::FeatureModel::NonBooleanConstraint::constraint,
+          R"pbdoc(Get underlying constraint.)pbdoc");
+
+  py::enum_<vf::FeatureModel::MixedConstraint::Req>(M, "Req")
+      .value("ALL", vf::FeatureModel::MixedConstraint::Req::ALL)
+      .value("NONE", vf::FeatureModel::MixedConstraint::Req::NONE);
+  py::enum_<vf::FeatureModel::MixedConstraint::ExprKind>(M, "ExprKind")
+      .value("POS", vf::FeatureModel::MixedConstraint::ExprKind::POS)
+      .value("NEG", vf::FeatureModel::MixedConstraint::ExprKind::NEG);
+  py::class_<vf::FeatureModel::MixedConstraint>(M, "MixedConstraint")
+      .def(py::init([](vf::Constraint &C,
+                       vf::FeatureModel::MixedConstraint::Req R,
+                       vf::FeatureModel::MixedConstraint::ExprKind E) {
+        return std::make_unique<vf::FeatureModel::MixedConstraint>(C.clone(), R,
+                                                                   E);
+      }))
+      .def("__str__", &vf::FeatureModel::MixedConstraint::toString)
+      .def_property_readonly("req", &vf::FeatureModel::MixedConstraint::req)
+      .def_property_readonly("exprKind",
+                             &vf::FeatureModel::MixedConstraint::exprKind)
+      .def_property_readonly("constraint",
+                             &vf::FeatureModel::MixedConstraint::constraint,
+                             R"pbdoc(Get underlying constraint.)pbdoc");
+
   py::class_<vf::FeatureModel>(M, "FeatureModel")
       .def_property_readonly(
           "name", &vf::FeatureModel::getName,
@@ -99,7 +139,24 @@ void init_feature_model_module(py::module &M) {
           [](const vf::FeatureModel &FM) {
             return py::make_iterator(FM.begin(), FM.end());
           },
-          py::keep_alive<0, 1>());
+          py::keep_alive<0, 1>())
+      .def_property_readonly("booleanConstraints",
+                             [](const vf::FeatureModel &FM) {
+                               return py::make_iterator(
+                                   FM.booleanConstraints().begin(),
+                                   FM.booleanConstraints().end());
+                             })
+      .def_property_readonly("nonBooleanConstraints",
+                             [](const vf::FeatureModel &FM) {
+                               return py::make_iterator(
+                                   FM.nonBooleanConstraints().begin(),
+                                   FM.nonBooleanConstraints().end());
+                             })
+      .def_property_readonly(
+          "mixedConstraints", [](const vf::FeatureModel &FM) {
+            return py::make_iterator(FM.mixedConstraints().begin(),
+                                     FM.mixedConstraints().end());
+          });
   M.def(
       "loadFeatureModel",
       [](const std::filesystem::path &Path) {
diff --git a/include/vara/Feature/FeatureModel.h b/include/vara/Feature/FeatureModel.h
index be1e2885b..af98ee877 100644
--- a/include/vara/Feature/FeatureModel.h
+++ b/include/vara/Feature/FeatureModel.h
@@ -6,6 +6,7 @@
 #include "vara/Feature/Feature.h"
 #include "vara/Feature/Relationship.h"
 #include "vara/Utils/Result.h"
+#include "vara/Utils/UniqueIterator.h"
 
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringMap.h"
@@ -236,12 +237,19 @@ class FeatureModel {
   /// \brief Base for different constraint kinds (boolean, non-boolean, etc.).
   class FeatureModelConstraint {
   public:
-    FeatureModelConstraint(std::unique_ptr<Constraint> C) : C(std::move(C)) {}
+    virtual ~FeatureModelConstraint() = default;
 
     [[nodiscard]] Constraint *constraint() { return C.get(); }
 
     [[nodiscard]] Constraint *operator*() { return C.get(); }
 
+    [[nodiscard]] virtual std::string toString() const { return C->toString(); }
+
+    [[nodiscard]] virtual std::string toHTML() const { return C->toHTML(); }
+
+  protected:
+    FeatureModelConstraint(std::unique_ptr<Constraint> C) : C(std::move(C)) {}
+
   private:
     std::unique_ptr<Constraint> C;
   };
@@ -256,12 +264,13 @@ class FeatureModel {
   using BooleanConstraintContainerTy =
       std::vector<std::unique_ptr<BooleanConstraint>>;
   using const_boolean_constraint_iterator =
-      typename BooleanConstraintContainerTy::const_iterator;
+      UniqueIterator<const BooleanConstraintContainerTy>;
 
   [[nodiscard]] llvm::iterator_range<const_boolean_constraint_iterator>
   booleanConstraints() const {
-    return llvm::make_range(BooleanConstraints.begin(),
-                            BooleanConstraints.end());
+    return llvm::make_range(
+        const_boolean_constraint_iterator(BooleanConstraints.begin()),
+        const_boolean_constraint_iterator(BooleanConstraints.end()));
   }
 
   class NonBooleanConstraint : public FeatureModelConstraint {
@@ -273,12 +282,13 @@ class FeatureModel {
   using NonBooleanConstraintContainerTy =
       std::vector<std::unique_ptr<NonBooleanConstraint>>;
   using const_non_boolean_constraint_iterator =
-      typename NonBooleanConstraintContainerTy::const_iterator;
+      UniqueIterator<const NonBooleanConstraintContainerTy>;
 
   [[nodiscard]] llvm::iterator_range<const_non_boolean_constraint_iterator>
   nonBooleanConstraints() const {
-    return llvm::make_range(NonBooleanConstraints.begin(),
-                            NonBooleanConstraints.end());
+    return llvm::make_range(
+        const_non_boolean_constraint_iterator(NonBooleanConstraints.begin()),
+        const_non_boolean_constraint_iterator(NonBooleanConstraints.end()));
   }
 
   class MixedConstraint : public FeatureModelConstraint {
@@ -306,11 +316,13 @@ class FeatureModel {
   using MixedConstraintContainerTy =
       std::vector<std::unique_ptr<MixedConstraint>>;
   using const_mixed_constraint_iterator =
-      typename MixedConstraintContainerTy::const_iterator;
+      UniqueIterator<const MixedConstraintContainerTy>;
 
   [[nodiscard]] llvm::iterator_range<const_mixed_constraint_iterator>
   mixedConstraints() const {
-    return llvm::make_range(MixedConstraints.begin(), MixedConstraints.end());
+    return llvm::make_range(
+        const_mixed_constraint_iterator(MixedConstraints.begin()),
+        const_mixed_constraint_iterator(MixedConstraints.end()));
   }
 
   //===--------------------------------------------------------------------===//
@@ -388,12 +400,13 @@ class FeatureModel {
   }
 
   using boolean_constraint_iterator =
-      typename BooleanConstraintContainerTy::iterator;
+      UniqueIterator<BooleanConstraintContainerTy>;
 
   [[nodiscard]] llvm::iterator_range<boolean_constraint_iterator>
   booleanConstraints() {
-    return llvm::make_range(BooleanConstraints.begin(),
-                            BooleanConstraints.end());
+    return llvm::make_range(
+        boolean_constraint_iterator(BooleanConstraints.begin()),
+        boolean_constraint_iterator(BooleanConstraints.end()));
   }
 
   vara::feature::Constraint *
@@ -403,12 +416,13 @@ class FeatureModel {
   }
 
   using non_boolean_constraint_iterator =
-      typename NonBooleanConstraintContainerTy::iterator;
+      UniqueIterator<NonBooleanConstraintContainerTy>;
 
   [[nodiscard]] llvm::iterator_range<non_boolean_constraint_iterator>
   nonBooleanConstraints() {
-    return llvm::make_range(NonBooleanConstraints.begin(),
-                            NonBooleanConstraints.end());
+    return llvm::make_range(
+        non_boolean_constraint_iterator(NonBooleanConstraints.begin()),
+        non_boolean_constraint_iterator(NonBooleanConstraints.end()));
   }
 
   vara::feature::Constraint *addConstraint(std::unique_ptr<MixedConstraint> C) {
@@ -416,12 +430,12 @@ class FeatureModel {
     return **MixedConstraints.back();
   }
 
-  using mixed_constraint_iterator =
-      typename MixedConstraintContainerTy::iterator;
+  using mixed_constraint_iterator = UniqueIterator<MixedConstraintContainerTy>;
 
   [[nodiscard]] llvm::iterator_range<mixed_constraint_iterator>
   mixedConstraints() {
-    return llvm::make_range(MixedConstraints.begin(), MixedConstraints.end());
+    return llvm::make_range(mixed_constraint_iterator(MixedConstraints.begin()),
+                            mixed_constraint_iterator(MixedConstraints.end()));
   }
 
   //===--------------------------------------------------------------------===//
diff --git a/include/vara/Utils/UniqueIterator.h b/include/vara/Utils/UniqueIterator.h
new file mode 100644
index 000000000..f03a85e28
--- /dev/null
+++ b/include/vara/Utils/UniqueIterator.h
@@ -0,0 +1,56 @@
+#ifndef VARA_UTILS_UNIQUEITERATOR_H
+#define VARA_UTILS_UNIQUEITERATOR_H
+
+#include <type_traits>
+
+namespace vara {
+
+//===----------------------------------------------------------------------===//
+//                            UniqueIterator Class
+//===----------------------------------------------------------------------===//
+
+template <typename ContainerTy,
+          typename ContainedTy = typename ContainerTy::value_type::element_type,
+          typename IteratorTy =
+              typename std::conditional<std::is_const<ContainerTy>::value,
+                                        typename ContainerTy::const_iterator,
+                                        typename ContainerTy::iterator>::type>
+class UniqueIterator {
+public:
+  UniqueIterator(IteratorTy Iterator) : Iterator{Iterator} {}
+  UniqueIterator(const UniqueIterator &) = default;
+  UniqueIterator &operator=(const UniqueIterator &) = delete;
+  UniqueIterator(UniqueIterator &&) noexcept = default;
+  UniqueIterator &operator=(UniqueIterator &&) = delete;
+  ~UniqueIterator() = default;
+
+  ContainedTy *operator*() const { return Iterator->get(); }
+
+  ContainedTy *operator->() const { return operator*(); }
+
+  UniqueIterator operator++() {
+    ++Iterator;
+    return *this;
+  }
+
+  UniqueIterator operator++(int) {
+    auto Iter(*this);
+    ++*this;
+    return Iter;
+  }
+
+  bool operator==(const UniqueIterator &Other) const {
+    return Iterator == Other.Iterator;
+  }
+
+  bool operator!=(const UniqueIterator &Other) const {
+    return !(*this == Other);
+  }
+
+private:
+  IteratorTy Iterator;
+};
+
+} // namespace vara
+
+#endif // VARA_UTILS_UNIQUEITERATOR_H
diff --git a/unittests/Feature/FeatureModelBuilder.cpp b/unittests/Feature/FeatureModelBuilder.cpp
index 810498230..c193529ca 100644
--- a/unittests/Feature/FeatureModelBuilder.cpp
+++ b/unittests/Feature/FeatureModelBuilder.cpp
@@ -99,7 +99,7 @@ TEST(FeatureModelBuilder, addOrConstraint) {
   ASSERT_TRUE(FM);
 
   EXPECT_EQ(
-      (*FM->booleanConstraints().begin())->constraint()->getRoot()->toString(),
+      FM->booleanConstraints().begin()->constraint()->getRoot()->toString(),
       Expected);
   EXPECT_EQ(
       (*FM->getFeature("a")->constraints().begin())->getRoot()->toString(),
@@ -122,11 +122,9 @@ TEST(FeatureModelBuilder, addNonBooleanConstraint) {
   std::unique_ptr<const FeatureModel> FM = B.buildFeatureModel();
   ASSERT_TRUE(FM);
 
-  EXPECT_EQ((*FM->nonBooleanConstraints().begin())
-                ->constraint()
-                ->getRoot()
-                ->toString(),
-            Expected);
+  EXPECT_EQ(
+      FM->nonBooleanConstraints().begin()->constraint()->getRoot()->toString(),
+      Expected);
   EXPECT_EQ(
       (*FM->getFeature("a")->constraints().begin())->getRoot()->toString(),
       Expected);
@@ -152,12 +150,11 @@ TEST(FeatureModelBuilder, addMixedConstraint) {
   std::unique_ptr<const FeatureModel> FM = B.buildFeatureModel();
   ASSERT_TRUE(FM);
 
-  EXPECT_EQ(
-      (*FM->mixedConstraints().begin())->constraint()->getRoot()->toString(),
-      Expected);
-  EXPECT_EQ((*FM->mixedConstraints().begin())->req(),
+  EXPECT_EQ(FM->mixedConstraints().begin()->constraint()->getRoot()->toString(),
+            Expected);
+  EXPECT_EQ(FM->mixedConstraints().begin()->req(),
             FeatureModel::MixedConstraint::Req::ALL);
-  EXPECT_EQ((*FM->mixedConstraints().begin())->exprKind(),
+  EXPECT_EQ(FM->mixedConstraints().begin()->exprKind(),
             FeatureModel::MixedConstraint::ExprKind::POS);
   EXPECT_EQ(
       (*FM->getFeature("a")->constraints().begin())->getRoot()->toString(),
diff --git a/unittests/Feature/FeatureModelParser.cpp b/unittests/Feature/FeatureModelParser.cpp
index 5a31ca61c..146a78fb3 100644
--- a/unittests/Feature/FeatureModelParser.cpp
+++ b/unittests/Feature/FeatureModelParser.cpp
@@ -117,7 +117,7 @@ TEST(FeatureModelParser, booleanConstraint) {
   ASSERT_TRUE(FM);
 
   EXPECT_EQ(
-      (*FM->booleanConstraints().begin())->constraint()->getRoot()->toString(),
+      FM->booleanConstraints().begin()->constraint()->getRoot()->toString(),
       C.toString());
 }
 
@@ -130,11 +130,9 @@ TEST(FeatureModelParser, nonBooleanConstraint) {
   auto FM = buildFeatureModel("test_constraints.xml");
   ASSERT_TRUE(FM);
 
-  EXPECT_EQ((*FM->nonBooleanConstraints().begin())
-                ->constraint()
-                ->getRoot()
-                ->toString(),
-            C.toString());
+  EXPECT_EQ(
+      FM->nonBooleanConstraints().begin()->constraint()->getRoot()->toString(),
+      C.toString());
 }
 
 TEST(FeatureModelParser, mixedConstraint) {
@@ -148,12 +146,11 @@ TEST(FeatureModelParser, mixedConstraint) {
   auto FM = buildFeatureModel("test_constraints.xml");
   ASSERT_TRUE(FM);
 
-  EXPECT_EQ(
-      (*FM->mixedConstraints().begin())->constraint()->getRoot()->toString(),
-      C.toString());
-  EXPECT_EQ((*FM->mixedConstraints().begin())->req(),
+  EXPECT_EQ(FM->mixedConstraints().begin()->constraint()->getRoot()->toString(),
+            C.toString());
+  EXPECT_EQ(FM->mixedConstraints().begin()->req(),
             FeatureModel::MixedConstraint::Req::ALL);
-  EXPECT_EQ((*FM->mixedConstraints().begin())->exprKind(),
+  EXPECT_EQ(FM->mixedConstraints().begin()->exprKind(),
             FeatureModel::MixedConstraint::ExprKind::POS);
 }
 
diff --git a/unittests/resources/xml/vm.dtd b/unittests/resources/xml/vm.dtd
index 1ef8ac061..7e91dd25b 100644
--- a/unittests/resources/xml/vm.dtd
+++ b/unittests/resources/xml/vm.dtd
@@ -1,5 +1,5 @@
 <!ELEMENT vm (binaryOptions, numericOptions?, booleanConstraints?, nonBooleanConstraints?, mixedConstraints?)>
-<!ATTLIST vm name CDATA #REQUIRED root CDATA #IMPLIED>
+<!ATTLIST vm name CDATA #REQUIRED root CDATA #IMPLIED commit CDATA #IMPLIED>
 <!ELEMENT binaryOptions (configurationOption*)>
 <!ELEMENT numericOptions (configurationOption*)>
 <!ELEMENT booleanConstraints (constraint*)>