diff --git a/internal/domains/sensors/domain.go b/internal/domains/sensors/domain.go
index 30144e2..51cba65 100644
--- a/internal/domains/sensors/domain.go
+++ b/internal/domains/sensors/domain.go
@@ -38,12 +38,36 @@ func (s *Sensor) Validate() error {
 	return nil
 }
 
+func (d *SensorData) Validate() error {
+	if d.SensorID == "" {
+		return ErrInvalidSensorIdentifier
+	}
+
+	if d.Value == nil {
+		return ErrMissingValue
+	}
+
+	if d.Timestamp == nil {
+		now := time.Now()
+		d.Timestamp = &now
+	}
+
+	return nil
+}
+
+// TODO: implement this in service layer for alerts
 func (d *SensorData) IsOutOfRangeAbove(sensor Sensor) bool {
-	return d.Value > *sensor.ThresholdAbove
+	if d.Value == nil || sensor.ThresholdAbove == nil {
+		return false
+	}
+	return *d.Value > *sensor.ThresholdAbove
 }
 
 func (d *SensorData) IsOutOfRangeBelow(sensor Sensor) bool {
-	return d.Value < *sensor.ThresholdBelow
+	if d.Value == nil || sensor.ThresholdBelow == nil {
+		return false
+	}
+	return *d.Value < *sensor.ThresholdBelow
 }
 
 func (r *SensorRequest) Validate() error {
diff --git a/internal/domains/sensors/domain_test.go b/internal/domains/sensors/domain_test.go
index 860da70..038a8af 100644
--- a/internal/domains/sensors/domain_test.go
+++ b/internal/domains/sensors/domain_test.go
@@ -208,8 +208,8 @@ func Test_SensorData_IsOutOfRangeAbove(t *testing.T) {
 			name: "value above threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     150.0,
-				Timestamp: time.Now(),
+				Value:     ptr(150.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -221,8 +221,8 @@ func Test_SensorData_IsOutOfRangeAbove(t *testing.T) {
 			name: "value below threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     50.0,
-				Timestamp: time.Now(),
+				Value:     ptr(50.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -234,8 +234,8 @@ func Test_SensorData_IsOutOfRangeAbove(t *testing.T) {
 			name: "value equal to threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     100.0,
-				Timestamp: time.Now(),
+				Value:     ptr(100.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -247,8 +247,8 @@ func Test_SensorData_IsOutOfRangeAbove(t *testing.T) {
 			name: "negative value above negative threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     -5.0,
-				Timestamp: time.Now(),
+				Value:     ptr(-5.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -282,8 +282,8 @@ func Test_SensorData_IsOutOfRangeBelow(t *testing.T) {
 			name: "value below threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     5.0,
-				Timestamp: time.Now(),
+				Value:     ptr(5.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -295,8 +295,8 @@ func Test_SensorData_IsOutOfRangeBelow(t *testing.T) {
 			name: "value above threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     50.0,
-				Timestamp: time.Now(),
+				Value:     ptr(50.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -308,8 +308,8 @@ func Test_SensorData_IsOutOfRangeBelow(t *testing.T) {
 			name: "value equal to threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     10.0,
-				Timestamp: time.Now(),
+				Value:     ptr(10.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -321,8 +321,8 @@ func Test_SensorData_IsOutOfRangeBelow(t *testing.T) {
 			name: "negative value below threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     -15.0,
-				Timestamp: time.Now(),
+				Value:     ptr(-15.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
@@ -334,8 +334,8 @@ func Test_SensorData_IsOutOfRangeBelow(t *testing.T) {
 			name: "zero value below positive threshold",
 			data: SensorData{
 				SensorID:  "temp-001",
-				Value:     0.0,
-				Timestamp: time.Now(),
+				Value:     ptr(0.0),
+				Timestamp: ptr(time.Now()),
 			},
 			sensor: Sensor{
 				SensorID:       "temp-001",
diff --git a/internal/domains/sensors/models.go b/internal/domains/sensors/models.go
index 0c7f58a..04d0d4f 100644
--- a/internal/domains/sensors/models.go
+++ b/internal/domains/sensors/models.go
@@ -15,18 +15,18 @@ const (
 )
 
 type Sensor struct {
-	SensorID         string         `json:"sensor_id"`
-	SensorType       SType          `json:"sensor_type"`
-	SamplingInterval *time.Duration `json:"sampling"`
-	ThresholdAbove   *float64       `json:"thresoldabove"`
-	ThresholdBelow   *float64       `json:"thresoldbelow"`
-	SensorData       *[]SensorData  `json:"sensor_data,omitempty"`
+	SensorID         string              `json:"sensor_id"`
+	SensorType       SType               `json:"sensor_type"`
+	SamplingInterval *time.Duration      `json:"sampling"`
+	ThresholdAbove   *float64            `json:"thresoldabove"`
+	ThresholdBelow   *float64            `json:"thresoldbelow"`
+	SensorData       *map[int]SensorData `json:"sensor_data,omitempty"`
 }
 
 type SensorData struct {
-	SensorID  string    `json:"sensor_id"`
-	Value     float64   `json:"value"`
-	Timestamp time.Time `json:"timestamp"`
+	SensorID  string     `json:"sensor_id"`
+	Value     *float64   `json:"value"`
+	Timestamp *time.Time `json:"timestamp"`
 }
 
 type SensorRequest struct {