diff --git a/cpl-workspace.json b/cpl-workspace.json
index e00ea987..706e879e 100644
--- a/cpl-workspace.json
+++ b/cpl-workspace.json
@@ -6,6 +6,7 @@
       "cpl-core": "src/cpl_core/cpl-core.json",
       "cpl-discord": "src/cpl_discord/cpl-discord.json",
       "cpl-query": "src/cpl_query/cpl-query.json",
+      "cpl-reactive-extensions": "src/cpl_reactive_extensions/cpl-reactive-extensions.json",
       "cpl-translation": "src/cpl_translation/cpl-translation.json",
       "set-version": "tools/set_version/set-version.json",
       "set-pip-urls": "tools/set_pip_urls/set-pip-urls.json",
@@ -14,7 +15,8 @@
       "unittests_core": "unittests/unittests_core/unittests_core.json",
       "unittests_query": "unittests/unittests_query/unittests_query.json",
       "unittests_shared": "unittests/unittests_shared/unittests_shared.json",
-      "unittests_translation": "unittests/unittests_translation/unittests_translation.json"
+      "unittests_translation": "unittests/unittests_translation/unittests_translation.json",
+      "unittests_reactive_extenstions": "unittests/unittests_reactive_extenstions/unittests_reactive_extenstions.json"
     },
     "Scripts": {
       "hello-world": "echo 'Hello World'",
diff --git a/src/cpl_reactive_extensions/__init__.py b/src/cpl_reactive_extensions/__init__.py
new file mode 100644
index 00000000..425ab6c1
--- /dev/null
+++ b/src/cpl_reactive_extensions/__init__.py
@@ -0,0 +1 @@
+# imports
diff --git a/src/cpl_reactive_extensions/cpl-reactive-extensions.json b/src/cpl_reactive_extensions/cpl-reactive-extensions.json
new file mode 100644
index 00000000..bd851781
--- /dev/null
+++ b/src/cpl_reactive_extensions/cpl-reactive-extensions.json
@@ -0,0 +1,46 @@
+{
+  "ProjectSettings": {
+    "Name": "cpl-reactive-extensions",
+    "Version": {
+      "Major": "0",
+      "Minor": "0",
+      "Micro": "0"
+    },
+    "Author": "",
+    "AuthorEmail": "",
+    "Description": "",
+    "LongDescription": "",
+    "URL": "",
+    "CopyrightDate": "",
+    "CopyrightName": "",
+    "LicenseName": "",
+    "LicenseDescription": "",
+    "Dependencies": [
+      "cpl-core>=2023.4.0"
+    ],
+    "DevDependencies": [
+      "cpl-cli>=2023.4.0"
+    ],
+    "PythonVersion": ">=3.10.4",
+    "PythonPath": {
+      "linux": ""
+    },
+    "Classifiers": []
+  },
+  "BuildSettings": {
+    "ProjectType": "library",
+    "SourcePath": "",
+    "OutputPath": "../../dist",
+    "Main": "cpl_reactive_extensions.main",
+    "EntryPoint": "cpl-reactive-extensions",
+    "IncludePackageData": false,
+    "Included": [],
+    "Excluded": [
+      "*/__pycache__",
+      "*/logs",
+      "*/tests"
+    ],
+    "PackageData": {},
+    "ProjectReferences": []
+  }
+}
\ No newline at end of file
diff --git a/src/cpl_reactive_extensions/observable.py b/src/cpl_reactive_extensions/observable.py
new file mode 100644
index 00000000..88cefa3b
--- /dev/null
+++ b/src/cpl_reactive_extensions/observable.py
@@ -0,0 +1,19 @@
+from typing import Callable
+
+from cpl_reactive_extensions.observer import Observer
+
+
+class Observable:
+    def __init__(self, callback: Callable):
+        self._callback = callback
+        self._subscriptions: list[Callable] = []
+
+    def _run_subscriptions(self):
+        for callback in self._subscriptions:
+            callback()
+
+    def subscribe(self, observer: Observer):
+        try:
+            self._callback(observer)
+        except Exception as e:
+            observer.error(e)
diff --git a/src/cpl_reactive_extensions/observer.py b/src/cpl_reactive_extensions/observer.py
new file mode 100644
index 00000000..895b6a66
--- /dev/null
+++ b/src/cpl_reactive_extensions/observer.py
@@ -0,0 +1,24 @@
+from typing import Callable
+
+from cpl_core.type import T
+
+
+class Observer:
+    def __init__(self, on_next: Callable, on_error: Callable = None, on_complete: Callable = None):
+        self._on_next = on_next
+        self._on_error = on_error if on_error is not None else lambda err: err
+        self._on_complete = on_complete if on_complete is not None else lambda x: x
+
+    def next(self, value: T):
+        self._on_next(value)
+
+    def error(self, ex: Exception):
+        if self._on_error is None:
+            return
+        self._on_error(ex)
+
+    def complete(self):
+        if self._on_complete is None:
+            return
+
+        self._on_complete()
diff --git a/src/cpl_reactive_extensions/subject.py b/src/cpl_reactive_extensions/subject.py
new file mode 100644
index 00000000..679f8ac1
--- /dev/null
+++ b/src/cpl_reactive_extensions/subject.py
@@ -0,0 +1,17 @@
+from cpl_core.type import T
+from cpl_reactive_extensions.observable import Observable
+
+
+class Subject(Observable):
+    def __init__(self):
+        Observable.__init__(self)
+
+        self._value: T = None
+
+    @property
+    def value(self) -> T:
+        return self._value
+
+    def emit(self, value: T):
+        self._value = value
+        self._subscriptions()
diff --git a/unittests/unittests/application.py b/unittests/unittests/application.py
index 932fb34b..95a4854f 100644
--- a/unittests/unittests/application.py
+++ b/unittests/unittests/application.py
@@ -6,6 +6,7 @@ from cpl_core.dependency_injection import ServiceProviderABC
 from unittests_cli.cli_test_suite import CLITestSuite
 from unittests_core.core_test_suite import CoreTestSuite
 from unittests_query.query_test_suite import QueryTestSuite
+from unittests_reactive_extenstions.reactive_test_suite import ReactiveTestSuite
 from unittests_translation.translation_test_suite import TranslationTestSuite
 
 
@@ -21,4 +22,5 @@ class Application(ApplicationABC):
         runner.run(CoreTestSuite())
         runner.run(CLITestSuite())
         runner.run(QueryTestSuite())
+        runner.run(ReactiveTestSuite())
         runner.run(TranslationTestSuite())
diff --git a/unittests/unittests_reactive_extenstions/__init__.py b/unittests/unittests_reactive_extenstions/__init__.py
new file mode 100644
index 00000000..425ab6c1
--- /dev/null
+++ b/unittests/unittests_reactive_extenstions/__init__.py
@@ -0,0 +1 @@
+# imports
diff --git a/unittests/unittests_reactive_extenstions/reactive_test_case.py b/unittests/unittests_reactive_extenstions/reactive_test_case.py
new file mode 100644
index 00000000..e0ee498f
--- /dev/null
+++ b/unittests/unittests_reactive_extenstions/reactive_test_case.py
@@ -0,0 +1,71 @@
+import unittest
+from threading import Timer
+
+from cpl_reactive_extensions.observable import Observable
+from cpl_reactive_extensions.observer import Observer
+
+
+class ReactiveTestCase(unittest.TestCase):
+    def setUp(self):
+        pass
+
+    def test_observer(self):
+        called = 0
+        has_error = False
+        completed = False
+        test_x = 1
+
+        def callback(observer: Observer):
+            nonlocal test_x
+            observer.next(test_x)
+            test_x += 1
+            observer.next(test_x)
+            test_x += 1
+            observer.next(test_x)
+
+            def complete():
+                nonlocal test_x
+                test_x += 1
+                observer.next(test_x)
+                observer.complete()
+
+            Timer(1.0, complete).start()
+
+        observable = Observable(callback)
+
+        def on_next(x):
+            nonlocal called
+            called += 1
+            self.assertEqual(test_x, x)
+
+        def on_err():
+            nonlocal has_error
+            has_error = True
+
+        def on_complete():
+            nonlocal completed
+            completed = True
+
+        self.assertEqual(called, 0)
+        self.assertFalse(has_error)
+        self.assertFalse(completed)
+        observable.subscribe(
+            Observer(
+                on_next,
+                on_err,
+                on_complete,
+            )
+        )
+        self.assertEqual(called, 3)
+        self.assertFalse(has_error)
+        self.assertFalse(completed)
+
+        def complete():
+            self.assertEqual(called, 4)
+            self.assertFalse(has_error)
+            self.assertTrue(completed)
+
+        Timer(1.0, complete).start()
+
+    def test_subject(self):
+        pass
diff --git a/unittests/unittests_reactive_extenstions/reactive_test_suite.py b/unittests/unittests_reactive_extenstions/reactive_test_suite.py
new file mode 100644
index 00000000..050700d3
--- /dev/null
+++ b/unittests/unittests_reactive_extenstions/reactive_test_suite.py
@@ -0,0 +1,24 @@
+import unittest
+
+from unittests_query.enumerable_query_test_case import EnumerableQueryTestCase
+from unittests_query.enumerable_test_case import EnumerableTestCase
+from unittests_query.iterable_query_test_case import IterableQueryTestCase
+from unittests_query.iterable_test_case import IterableTestCase
+from unittests_query.sequence_test_case import SequenceTestCase
+from unittests_reactive_extenstions.reactive_test_case import ReactiveTestCase
+
+
+class ReactiveTestSuite(unittest.TestSuite):
+    def __init__(self):
+        unittest.TestSuite.__init__(self)
+
+        loader = unittest.TestLoader()
+        self.addTests(loader.loadTestsFromTestCase(ReactiveTestCase))
+
+    def run(self, *args):
+        super().run(*args)
+
+
+if __name__ == "__main__":
+    runner = unittest.TextTestRunner()
+    runner.run(ReactiveTestSuite())
diff --git a/unittests/unittests_reactive_extenstions/unittests_reactive_extenstions.json b/unittests/unittests_reactive_extenstions/unittests_reactive_extenstions.json
new file mode 100644
index 00000000..8919eb59
--- /dev/null
+++ b/unittests/unittests_reactive_extenstions/unittests_reactive_extenstions.json
@@ -0,0 +1,46 @@
+{
+  "ProjectSettings": {
+    "Name": "unittests_reactive_extenstions",
+    "Version": {
+      "Major": "0",
+      "Minor": "0",
+      "Micro": "0"
+    },
+    "Author": "",
+    "AuthorEmail": "",
+    "Description": "",
+    "LongDescription": "",
+    "URL": "",
+    "CopyrightDate": "",
+    "CopyrightName": "",
+    "LicenseName": "",
+    "LicenseDescription": "",
+    "Dependencies": [
+      "cpl-core>=2023.4.0"
+    ],
+    "DevDependencies": [
+      "cpl-cli>=2023.4.0"
+    ],
+    "PythonVersion": ">=3.10.4",
+    "PythonPath": {
+      "linux": ""
+    },
+    "Classifiers": []
+  },
+  "BuildSettings": {
+    "ProjectType": "unittest",
+    "SourcePath": "",
+    "OutputPath": "../../dist",
+    "Main": "unittests_reactive_extenstions.main",
+    "EntryPoint": "unittests_reactive_extenstions",
+    "IncludePackageData": false,
+    "Included": [],
+    "Excluded": [
+      "*/__pycache__",
+      "*/logs",
+      "*/tests"
+    ],
+    "PackageData": {},
+    "ProjectReferences": []
+  }
+}
\ No newline at end of file