diff --git a/backend/tests/test_models.py b/backend/tests/test_models.py
new file mode 100644
index 0000000..59f9892
--- /dev/null
+++ b/backend/tests/test_models.py
@@ -0,0 +1,144 @@
+import pytest
+from datetime import datetime
+from pydantic import ValidationError
+
+from backend.app.models import CodecType, RecorderConfig, PortStatus, SCTE35Marker
+
+
+class TestCodecType:
+    """Test CodecType enum values"""
+    
+    def test_codec_type_values(self):
+        """Verify all codec types are defined"""
+        assert CodecType.PRORES.value == "prores"
+        assert CodecType.DNXHD.value == "dnxhd"
+        assert CodecType.UNCOMPRESSED.value == "uncompressed"
+        assert CodecType.H264.value == "h264"
+    
+    def test_codec_type_members(self):
+        """Verify codec type members exist"""
+        codec_names = {member.name for member in CodecType}
+        assert codec_names == {"PRORES", "DNXHD", "UNCOMPRESSED", "H264"}
+
+
+class TestRecorderConfig:
+    """Test RecorderConfig model"""
+    
+    def test_recorder_config_creation(self):
+        """Test basic RecorderConfig instantiation"""
+        config = RecorderConfig(
+            port_index=0,
+            codec=CodecType.PRORES,
+            bitrate=100,
+            quality_profile="high",
+            recording_path="/recordings",
+            srt_enabled=True,
+            srt_destination="192.168.1.10:1234",
+            preview_enabled=True
+        )
+        assert config.port_index == 0
+        assert config.codec == CodecType.PRORES
+        assert config.bitrate == 100
+        assert config.quality_profile == "high"
+        assert config.recording_path == "/recordings"
+        assert config.srt_enabled is True
+        assert config.srt_destination == "192.168.1.10:1234"
+        assert config.preview_enabled is True
+    
+    def test_recorder_config_validation_port_index(self):
+        """Test port_index is required"""
+        with pytest.raises(ValidationError):
+            RecorderConfig(codec=CodecType.PRORES, bitrate=100)
+    
+    def test_recorder_config_codec_enum(self):
+        """Test codec must be CodecType enum"""
+        with pytest.raises(ValidationError):
+            RecorderConfig(
+                port_index=0,
+                codec="invalid",
+                bitrate=100
+            )
+
+
+class TestPortStatus:
+    """Test PortStatus model"""
+    
+    def test_port_status_creation(self):
+        """Test PortStatus instantiation"""
+        status = PortStatus(
+            port_index=1,
+            is_recording=True,
+            frame_count=1500,
+            fps=30,
+            bitrate_mbps=450,
+            uptime_seconds=120,
+            current_file="/recordings/port1_001.mxf",
+            codec=CodecType.DNXHD
+        )
+        assert status.port_index == 1
+        assert status.is_recording is True
+        assert status.frame_count == 1500
+        assert status.fps == 30
+        assert status.bitrate_mbps == 450
+        assert status.uptime_seconds == 120
+        assert status.current_file == "/recordings/port1_001.mxf"
+        assert status.codec == CodecType.DNXHD
+    
+    def test_port_status_with_defaults(self):
+        """Test PortStatus with minimal fields"""
+        status = PortStatus(
+            port_index=0,
+            is_recording=False,
+            frame_count=0,
+            fps=0,
+            bitrate_mbps=0,
+            uptime_seconds=0,
+            current_file="",
+            codec=CodecType.H264
+        )
+        assert status.port_index == 0
+        assert status.is_recording is False
+        assert status.frame_count == 0
+
+
+class TestSCTE35Marker:
+    """Test SCTE35Marker model"""
+    
+    def test_scte35_marker_creation(self):
+        """Test SCTE35Marker instantiation"""
+        marker = SCTE35Marker(
+            event_id="ad_001",
+            duration_seconds=30,
+            out_of_network=True,
+            splice_immediate=False,
+            timestamp=datetime(2026, 4, 14, 10, 30, 0),
+            webhook_url="https://example.com/webhook"
+        )
+        assert marker.event_id == "ad_001"
+        assert marker.duration_seconds == 30
+        assert marker.out_of_network is True
+        assert marker.splice_immediate is False
+        assert isinstance(marker.timestamp, datetime)
+        assert marker.webhook_url == "https://example.com/webhook"
+    
+    def test_scte35_marker_timestamp_generation(self):
+        """Test SCTE35Marker with auto-generated timestamp"""
+        before = datetime.utcnow()
+        marker = SCTE35Marker(
+            event_id="ad_002",
+            duration_seconds=60,
+            out_of_network=False,
+            splice_immediate=True,
+            timestamp=datetime.utcnow(),
+            webhook_url="https://api.example.com/events"
+        )
+        after = datetime.utcnow()
+        assert before <= marker.timestamp <= after
+    
+    def test_scte35_marker_fields_required(self):
+        """Test that required fields are enforced"""
+        with pytest.raises(ValidationError):
+            SCTE35Marker(
+                event_id="ad_003",
+                duration_seconds=30
+            )