diff --git a/cmd/server/main.go b/cmd/server/main.go
index 797fc9e..5894921 100644
--- a/cmd/server/main.go
+++ b/cmd/server/main.go
@@ -108,7 +108,7 @@ func main() {
 	r.Use(gin.Recovery())
 	r.Use(middleware.GinLogger())
 
-	h := &handler.Handler{DB: sqlDB, JWTSecret: cfg.Server.JWTSecret}
+	h := &handler.Handler{DB: sqlDB, JWTSecret: cfg.Server.JWTSecret, MQTTTopic: cfg.MQTT.Topic}
 
 	// Public routes
 	r.GET("/health", h.Health)
@@ -126,12 +126,14 @@ func main() {
 	auth.GET("/messages", handler.GetMessages)
 	auth.GET("/sensors", h.GetSensors)
 	auth.GET("/sensors/:id", h.GetSensor)
+	auth.POST("/sensors/:id/trigger", h.TriggerSensor)
 	auth.POST("/sensors", h.CreateSensor)
 	auth.PUT("/sensors/:id", h.UpdateSensor)
 	auth.DELETE("/sensors/:id", h.DeleteSensor)
 
 	auth.GET("/actors", h.GetActors)
 	auth.GET("/actors/:id", h.GetActor)
+	auth.POST("/actors/:id/write", h.WriteActor)
 	auth.POST("/actors", h.CreateActor)
 	auth.PUT("/actors/:id", h.UpdateActor)
 	auth.DELETE("/actors/:id", h.DeleteActor)
diff --git a/internal/handler/handlers.go b/internal/handler/handlers.go
index 9fca862..6bb77d1 100644
--- a/internal/handler/handlers.go
+++ b/internal/handler/handlers.go
@@ -2,11 +2,14 @@ package handler
 
 import (
 	"database/sql"
+	"encoding/json"
 	"net/http"
+	"os"
 	"strconv"
 	"strings"
 	"time"
 
+	"git.piskot.si/SeminarM2/lambdaiot-core/internal/mqtt"
 	"git.piskot.si/SeminarM2/lambdaiot-core/internal/storage"
 	"github.com/gin-gonic/gin"
 	"github.com/golang-jwt/jwt/v5"
@@ -16,6 +19,7 @@ import (
 type Handler struct {
 	DB        *sql.DB
 	JWTSecret string
+	MQTTTopic string
 }
 
 type Device struct {
@@ -55,6 +59,30 @@ type SensorReading struct {
 	ValueAt  time.Time `json:"value_at" db:"value_at"`
 }
 
+func (h *Handler) mqttTopic() string {
+	if h != nil && h.MQTTTopic != "" {
+		return h.MQTTTopic
+	}
+	if v := os.Getenv("MQTT_TOPIC"); v != "" {
+		return v
+	}
+	return "lambdaiot"
+}
+
+func (h *Handler) publishMQTT(c *gin.Context, payload any) bool {
+	topic := h.mqttTopic()
+	body, err := json.Marshal(payload)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to marshal payload"})
+		return false
+	}
+	if err := mqtt.PublishDefault(topic, body); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return false
+	}
+	return true
+}
+
 // Health returns basic service health
 func (h *Handler) Health(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"status": "ok"})
@@ -237,6 +265,58 @@ func (h *Handler) DeleteSensor(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"message": "sensor deleted"})
 }
 
+// TriggerSensor sends an MQTT message requesting a new reading from the sensor.
+// The message payload contains the sensor ID and the requested action (default "read").
+func (h *Handler) TriggerSensor(c *gin.Context) {
+	sensorID, err := uuid.Parse(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid sensor id"})
+		return
+	}
+
+	var exists int
+	if err := h.DB.QueryRow("SELECT COUNT(1) FROM sensors WHERE id = UUID_TO_BIN(?)", sensorID.String()).Scan(&exists); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to check sensor"})
+		return
+	}
+	if exists == 0 {
+		c.JSON(http.StatusNotFound, gin.H{"error": "sensor not found"})
+		return
+	}
+
+	var req struct {
+		Action string `json:"action"`
+	}
+	if c.Request.ContentLength > 0 {
+		if err := c.ShouldBindJSON(&req); err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+	}
+	action := req.Action
+	if action == "" {
+		action = "read"
+	}
+
+	payload := struct {
+		Type        string `json:"type"`
+		SensorID    string `json:"sensor_id"`
+		Action      string `json:"action"`
+		RequestedAt string `json:"requested_at"`
+	}{
+		Type:        "sensor_trigger",
+		SensorID:    sensorID.String(),
+		Action:      action,
+		RequestedAt: time.Now().UTC().Format(time.RFC3339),
+	}
+
+	if !h.publishMQTT(c, payload) {
+		return
+	}
+
+	c.JSON(http.StatusAccepted, gin.H{"status": "published", "topic": h.mqttTopic()})
+}
+
 // CreateDevice creates a new device
 func (h *Handler) CreateDevice(c *gin.Context) {
 	var req struct {
@@ -555,6 +635,54 @@ func (h *Handler) DeleteActor(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"message": "actor deleted"})
 }
 
+// WriteActor publishes a desired action/value for the actor to the MQTT topic.
+func (h *Handler) WriteActor(c *gin.Context) {
+	actorID, err := uuid.Parse(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid actor id"})
+		return
+	}
+
+	var exists int
+	if err := h.DB.QueryRow("SELECT COUNT(1) FROM actors WHERE id = UUID_TO_BIN(?)", actorID.String()).Scan(&exists); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to check actor"})
+		return
+	}
+	if exists == 0 {
+		c.JSON(http.StatusNotFound, gin.H{"error": "actor not found"})
+		return
+	}
+
+	var req struct {
+		Action string          `json:"action" binding:"required"`
+		Value  json.RawMessage `json:"value"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	payload := struct {
+		Type        string          `json:"type"`
+		ActorID     string          `json:"actor_id"`
+		Action      string          `json:"action"`
+		Value       json.RawMessage `json:"value,omitempty"`
+		RequestedAt string          `json:"requested_at"`
+	}{
+		Type:        "actor_command",
+		ActorID:     actorID.String(),
+		Action:      req.Action,
+		Value:       req.Value,
+		RequestedAt: time.Now().UTC().Format(time.RFC3339),
+	}
+
+	if !h.publishMQTT(c, payload) {
+		return
+	}
+
+	c.JSON(http.StatusAccepted, gin.H{"status": "published", "topic": h.mqttTopic()})
+}
+
 // Sensor readings CRUD
 func (h *Handler) CreateSensorReading(c *gin.Context) {
 	var req struct {
diff --git a/internal/handler/mqttping.go b/internal/handler/mqttping.go
index 198f009..4baa6f0 100644
--- a/internal/handler/mqttping.go
+++ b/internal/handler/mqttping.go
@@ -2,23 +2,16 @@ package handler
 
 import (
 	"net/http"
-	"os"
 	"time"
 
-	"git.piskot.si/SeminarM2/lambdaiot-core/internal/mqtt"
 	"github.com/gin-gonic/gin"
 )
 
 // MQTTPing publishes the current timestamp to the configured MQTT topic
 func (h *Handler) MQTTPing(c *gin.Context) {
-	ts := time.Now().Format(time.RFC3339)
-	topic := os.Getenv("MQTT_TOPIC")
-	if topic == "" {
-		topic = "lambdaiot"
-	}
-	if err := mqtt.PublishDefault(topic, []byte(ts)); err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+	ts := time.Now().UTC().Format(time.RFC3339)
+	if !h.publishMQTT(c, gin.H{"type": "ping", "timestamp": ts}) {
 		return
 	}
-	c.JSON(http.StatusOK, gin.H{"timestamp": ts})
+	c.JSON(http.StatusOK, gin.H{"timestamp": ts, "topic": h.mqttTopic()})
 }