diff --git a/api/src/Repositories/RepositoryException.php b/api/src/Repositories/RepositoryException.php
new file mode 100644
index 0000000..4d86fd9
--- /dev/null
+++ b/api/src/Repositories/RepositoryException.php
@@ -0,0 +1,12 @@
+<?php
+
+
+namespace TorstenHettstedt\TimekeepingApi\Repositories;
+
+
+use Exception;
+
+class RepositoryException extends Exception
+{
+
+}
\ No newline at end of file
diff --git a/api/src/Repositories/RepositoryReaderInterface.php b/api/src/Repositories/RepositoryReaderInterface.php
new file mode 100644
index 0000000..00aa1dc
--- /dev/null
+++ b/api/src/Repositories/RepositoryReaderInterface.php
@@ -0,0 +1,28 @@
+<?php
+
+
+namespace TorstenHettstedt\TimekeepingApi\Repositories;
+
+/**
+ * @template T of \TorstenHettstedt\TimekeepingApi\Models\ModelInterface
+ */
+interface RepositoryReaderInterface
+{
+    /**
+     *
+     * Gibt alle vorhandenen Einträge zurück
+     *
+     * @return T[]
+     */
+    public function findAll(): array;
+
+    /**
+     * Gibt den Eintrag zurück, der durch die ID
+     *
+     * @param mixed $primary_key
+     *
+     * @return T
+     * @throws RepositoryRecordNotFoundException
+     */
+    public function findByKey(mixed $primary_key);
+}
\ No newline at end of file
diff --git a/api/src/Repositories/RepositoryRecordNotFoundException.php b/api/src/Repositories/RepositoryRecordNotFoundException.php
new file mode 100644
index 0000000..101ce78
--- /dev/null
+++ b/api/src/Repositories/RepositoryRecordNotFoundException.php
@@ -0,0 +1,10 @@
+<?php
+
+
+namespace TorstenHettstedt\TimekeepingApi\Repositories;
+
+
+class RepositoryRecordNotFoundException extends RepositoryException
+{
+
+}
\ No newline at end of file
diff --git a/api/src/Repositories/RepositoryWriterInterface.php b/api/src/Repositories/RepositoryWriterInterface.php
new file mode 100644
index 0000000..ea37211
--- /dev/null
+++ b/api/src/Repositories/RepositoryWriterInterface.php
@@ -0,0 +1,31 @@
+<?php
+
+
+namespace TorstenHettstedt\TimekeepingApi\Repositories;
+
+/**
+ * @template T of \TorstenHettstedt\TimekeepingApi\Models\ModelInterface
+ */
+interface RepositoryWriterInterface
+{
+    /**
+     * @param T $model
+     *
+     * @throws UnsupportedModelException
+     */
+    public function insert(mixed $model): void;
+
+    /**
+     * @param T $model
+     *
+     * @throws UnsupportedModelException
+     */
+    public function update(mixed $model): void;
+
+    /**
+     * @param T $model
+     *
+     * @throws UnsupportedModelException
+     */
+    public function delete(mixed $model): void;
+}
\ No newline at end of file
diff --git a/api/src/Repositories/UnsupportedModelException.php b/api/src/Repositories/UnsupportedModelException.php
new file mode 100644
index 0000000..ad6f180
--- /dev/null
+++ b/api/src/Repositories/UnsupportedModelException.php
@@ -0,0 +1,10 @@
+<?php
+
+
+namespace TorstenHettstedt\TimekeepingApi\Repositories;
+
+
+class UnsupportedModelException extends RepositoryException
+{
+
+}
\ No newline at end of file