diff --git a/app.go b/app.go
index 150ce60..dbd512f 100644
--- a/app.go
+++ b/app.go
@@ -38,11 +38,11 @@ type App struct {
 	service *Service
 	state   *StateImpl
 
-	scheduledActions  []scheduledAction
-	scheduleCount     int
-	entityListeners   map[string][]*EntityListener
-	entityListenersId int64
-	eventListeners    map[string][]*EventListener
+	scheduledActions   []scheduledAction
+	scheduleCount      int
+	entityListeners    map[string][]*EntityListener
+	entitySubscription websocket.Subscription
+	eventListeners     map[string][]*EventListener
 }
 
 // DurationString represents a duration, such as "2s" or "24h".
@@ -160,43 +160,46 @@ func NewApp(ctx context.Context, request NewAppRequest) (*App, error) {
 
 	httpClient := http.NewHttpClient(baseURL, request.HAAuthToken)
 
-	service := newService(conn)
 	state, err := newState(httpClient, request.HomeZoneEntityId)
 	if err != nil {
 		return nil, err
 	}
 
-	// Validate home zone
-	if err := validateHomeZone(state, request.HomeZoneEntityId); err != nil {
-		return nil, err
-	}
-
 	ctx, cancel := context.WithCancel(ctx)
-	return &App{
+
+	app := App{
 		conn:            conn,
 		ctx:             ctx,
 		ctxCancel:       cancel,
 		httpClient:      httpClient,
-		service:         service,
 		state:           state,
 		entityListeners: map[string][]*EntityListener{},
 		eventListeners:  map[string][]*EventListener{},
-	}, nil
+	}
+
+	app.service = newService(&app)
+
+	// Validate home zone
+	if err := validateHomeZone(state, request.HomeZoneEntityId); err != nil {
+		return nil, err
+	}
+
+	return &app, nil
 }
 
-func (a *App) Cleanup() {
-	if a.ctxCancel != nil {
-		a.ctxCancel()
+func (app *App) Cleanup() {
+	if app.ctxCancel != nil {
+		app.ctxCancel()
 	}
 }
 
-func (a *App) RegisterSchedules(schedules ...DailySchedule) {
+func (app *App) RegisterSchedules(schedules ...DailySchedule) {
 	for _, s := range schedules {
 		// realStartTime already set for sunset/sunrise
 		if s.isSunrise || s.isSunset {
-			s.nextRunTime = getNextSunRiseOrSet(a, s.isSunrise, s.sunOffset).Carbon2Time()
-			a.scheduledActions = append(a.scheduledActions, s)
-			a.scheduleCount++
+			s.nextRunTime = getNextSunRiseOrSet(app, s.isSunrise, s.sunOffset).Carbon2Time()
+			app.scheduledActions = append(app.scheduledActions, s)
+			app.scheduleCount++
 			continue
 		}
 
@@ -209,12 +212,12 @@ func (a *App) RegisterSchedules(schedules ...DailySchedule) {
 		}
 
 		s.nextRunTime = startTime.Carbon2Time()
-		a.scheduledActions = append(a.scheduledActions, s)
-		a.scheduleCount++
+		app.scheduledActions = append(app.scheduledActions, s)
+		app.scheduleCount++
 	}
 }
 
-func (a *App) RegisterIntervals(intervals ...Interval) {
+func (app *App) RegisterIntervals(intervals ...Interval) {
 	for _, i := range intervals {
 		if i.frequency == 0 {
 			slog.Error("A schedule must use either set frequency via Every()")
@@ -226,11 +229,11 @@ func (a *App) RegisterIntervals(intervals ...Interval) {
 		for i.nextRunTime.Before(now) {
 			i.nextRunTime = i.nextRunTime.Add(i.frequency)
 		}
-		a.scheduledActions = append(a.scheduledActions, i)
+		app.scheduledActions = append(app.scheduledActions, i)
 	}
 }
 
-func (a *App) RegisterEntityListeners(etls ...EntityListener) {
+func (app *App) RegisterEntityListeners(etls ...EntityListener) {
 	for _, etl := range etls {
 		etl := etl
 		if etl.delay != 0 && etl.toState == "" {
@@ -239,24 +242,24 @@ func (a *App) RegisterEntityListeners(etls ...EntityListener) {
 		}
 
 		for _, entity := range etl.entityIds {
-			if elList, ok := a.entityListeners[entity]; ok {
-				a.entityListeners[entity] = append(elList, &etl)
+			if elList, ok := app.entityListeners[entity]; ok {
+				app.entityListeners[entity] = append(elList, &etl)
 			} else {
-				a.entityListeners[entity] = []*EntityListener{&etl}
+				app.entityListeners[entity] = []*EntityListener{&etl}
 			}
 		}
 	}
 }
 
-func (a *App) RegisterEventListeners(evls ...EventListener) {
+func (app *App) RegisterEventListeners(evls ...EventListener) {
 	for _, evl := range evls {
 		evl := evl
 		for _, eventType := range evl.eventTypes {
-			if elList, ok := a.eventListeners[eventType]; ok {
-				a.eventListeners[eventType] = append(elList, &evl)
+			if elList, ok := app.eventListeners[eventType]; ok {
+				app.eventListeners[eventType] = append(elList, &evl)
 			} else {
-				websocket.SubscribeToEventType(a.ctx, eventType, a.conn)
-				a.eventListeners[eventType] = []*EventListener{&evl}
+				websocket.SubscribeToEventType(eventType, app.conn)
+				app.eventListeners[eventType] = []*EventListener{&evl}
 			}
 		}
 	}
@@ -295,41 +298,39 @@ func getSunriseSunset(s *StateImpl, sunrise bool, dateToUse carbon.Carbon, offse
 	return setOrRiseToday
 }
 
-func getNextSunRiseOrSet(a *App, sunrise bool, offset ...DurationString) carbon.Carbon {
-	sunriseOrSunset := getSunriseSunset(a.state, sunrise, carbon.Now(), offset...)
+func getNextSunRiseOrSet(app *App, sunrise bool, offset ...DurationString) carbon.Carbon {
+	sunriseOrSunset := getSunriseSunset(app.state, sunrise, carbon.Now(), offset...)
 	if sunriseOrSunset.Lt(carbon.Now()) {
 		// if we're past today's sunset or sunrise (accounting for offset) then get tomorrows
 		// as that's the next time the schedule will run
-		sunriseOrSunset = getSunriseSunset(a.state, sunrise, carbon.Tomorrow(), offset...)
+		sunriseOrSunset = getSunriseSunset(app.state, sunrise, carbon.Tomorrow(), offset...)
 	}
 	return sunriseOrSunset
 }
 
-func (a *App) Start() {
-	slog.Info("Starting", "schedules", a.scheduleCount)
-	slog.Info("Starting", "entity listeners", len(a.entityListeners))
-	slog.Info("Starting", "event listeners", len(a.eventListeners))
+func (app *App) Start() {
+	slog.Info("Starting", "schedules", app.scheduleCount)
+	slog.Info("Starting", "entity listeners", len(app.entityListeners))
+	slog.Info("Starting", "event listeners", len(app.eventListeners))
 
-	go a.runScheduledActions(a.ctx)
+	go app.runScheduledActions(app.ctx)
 
 	// subscribe to state_changed events
-	id := internal.GetId()
-	websocket.SubscribeToStateChangedEvents(a.ctx, id, a.conn)
-	a.entityListenersId = id
+	app.entitySubscription = websocket.SubscribeToStateChangedEvents(app.conn)
 
 	// entity listeners runOnStartup
-	for eid, etls := range a.entityListeners {
+	for eid, etls := range app.entityListeners {
 		for _, etl := range etls {
 			// ensure each ETL only runs once, even if
 			// it listens to multiple entities
 			if etl.runOnStartup && !etl.runOnStartupCompleted {
-				entityState, err := a.state.Get(eid)
+				entityState, err := app.state.Get(eid)
 				if err != nil {
 					slog.Warn("Failed to get entity state \"", eid, "\" during startup, skipping RunOnStartup")
 				}
 
 				etl.runOnStartupCompleted = true
-				go etl.callback(a.service, a.state, EntityData{
+				go etl.callback(app.service, app.state, EntityData{
 					TriggerEntityId: eid,
 					FromState:       entityState.State,
 					FromAttributes:  entityState.Attributes,
@@ -343,17 +344,17 @@ func (a *App) Start() {
 
 	// entity listeners and event listeners
 	elChan := make(chan websocket.ChanMsg)
-	go a.conn.ListenWebsocket(elChan)
+	go app.conn.ListenWebsocket(elChan)
 
 	for {
 		msg, ok := <-elChan
 		if !ok {
 			break
 		}
-		if a.entityListenersId == msg.Id {
-			go callEntityListeners(a, msg.Raw)
+		if app.entitySubscription.ID() == msg.Id {
+			go callEntityListeners(app, msg.Raw)
 		} else {
-			go callEventListeners(a, msg)
+			go callEventListeners(app, msg)
 		}
 	}
 }
@@ -362,23 +363,23 @@ func (a *App) Start() {
 // and each `Interval` that has been configured. The `run()` method of
 // each of those instances takes care of deciding when to run and
 // invoking its callback.
-func (a *App) runScheduledActions(ctx context.Context) {
+func (app *App) runScheduledActions(ctx context.Context) {
 	var wg sync.WaitGroup
 	defer wg.Wait()
 
-	for _, action := range a.scheduledActions {
+	for _, action := range app.scheduledActions {
 		wg.Add(1)
 		go func(action scheduledAction) {
 			defer wg.Done()
-			action.run(ctx, a)
+			action.run(ctx, app)
 		}(action)
 	}
 }
 
-func (a *App) GetService() *Service {
-	return a.service
+func (app *App) GetService() *Service {
+	return app.service
 }
 
-func (a *App) GetState() State {
-	return a.state
+func (app *App) GetState() State {
+	return app.state
 }
diff --git a/call.go b/call.go
new file mode 100644
index 0000000..c3c61fa
--- /dev/null
+++ b/call.go
@@ -0,0 +1,17 @@
+package gomeassistant
+
+import (
+	"saml.dev/gome-assistant/internal/services"
+	"saml.dev/gome-assistant/internal/websocket"
+)
+
+func (app *App) Call(req services.BaseServiceRequest) error {
+	req.RequestType = "call_service"
+
+	return app.conn.Send(
+		func(lc websocket.LockedConn) error {
+			req.Id = lc.NextMessageID()
+			return lc.SendMessage(req)
+		},
+	)
+}
diff --git a/fire_event.go b/fire_event.go
new file mode 100644
index 0000000..148cc79
--- /dev/null
+++ b/fire_event.go
@@ -0,0 +1,26 @@
+package gomeassistant
+
+import "saml.dev/gome-assistant/internal/websocket"
+
+func (app *App) FireEvent(eventType string, eventData map[string]any) error {
+	return app.conn.Send(
+		func(lc websocket.LockedConn) error {
+			req := FireEventRequest{
+				Id:        lc.NextMessageID(),
+				Type:      "fire_event",
+				EventType: eventType,
+				EventData: eventData,
+			}
+
+			return lc.SendMessage(req)
+		},
+	)
+}
+
+// Fire an event
+type FireEventRequest struct {
+	Id        int64          `json:"id"`
+	Type      string         `json:"type"` // always set to "fire_event"
+	EventType string         `json:"event_type"`
+	EventData map[string]any `json:"event_data,omitempty"`
+}
diff --git a/internal/internal.go b/internal/internal.go
index f5efc14..2e818cc 100644
--- a/internal/internal.go
+++ b/internal/internal.go
@@ -16,13 +16,6 @@ type EnabledDisabledInfo struct {
 	RunOnError bool
 }
 
-var id int64 = 0
-
-func GetId() int64 {
-	id += 1
-	return id
-}
-
 // Parses a HH:MM string.
 func ParseTime(s string) carbon.Carbon {
 	t, err := time.Parse("15:04", s)
diff --git a/internal/services/adaptive_lighting.go b/internal/services/adaptive_lighting.go
index abfb29f..c09485b 100644
--- a/internal/services/adaptive_lighting.go
+++ b/internal/services/adaptive_lighting.go
@@ -1,26 +1,24 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type AdaptiveLighting struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 // Set manual control for an adaptive lighting entity.
 func (al AdaptiveLighting) SetManualControl(entityId string, enabled bool) error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "adaptive_lighting"
-	req.Service = "set_manual_control"
-	req.ServiceData = map[string]any{
-		"entity_id":      entityId,
-		"manual_control": enabled,
+	req := BaseServiceRequest{
+		Domain:  "adaptive_lighting",
+		Service: "set_manual_control",
+		ServiceData: map[string]any{
+			"entity_id":      entityId,
+			"manual_control": enabled,
+		},
+		Target: Entity(entityId),
 	}
 
-	return al.conn.WriteMessage(req)
+	return al.api.Call(req)
 }
diff --git a/internal/services/alarm_control_panel.go b/internal/services/alarm_control_panel.go
index 3b8858e..fa02e65 100644
--- a/internal/services/alarm_control_panel.go
+++ b/internal/services/alarm_control_panel.go
@@ -1,13 +1,9 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type AlarmControlPanel struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
@@ -16,96 +12,110 @@ type AlarmControlPanel struct {
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (acp AlarmControlPanel) ArmAway(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "alarm_control_panel"
-	req.Service = "alarm_arm_away"
+	req := BaseServiceRequest{
+		Domain:  "alarm_control_panel",
+		Service: "alarm_arm_away",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return acp.conn.WriteMessage(req)
+	return acp.api.Call(req)
 }
 
 // Send the alarm the command for arm away.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (acp AlarmControlPanel) ArmWithCustomBypass(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "alarm_control_panel"
-	req.Service = "alarm_arm_custom_bypass"
+	req := BaseServiceRequest{
+		Domain:  "alarm_control_panel",
+		Service: "alarm_arm_custom_bypass",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return acp.conn.WriteMessage(req)
+	return acp.api.Call(req)
 }
 
 // Send the alarm the command for arm home.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (acp AlarmControlPanel) ArmHome(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "alarm_control_panel"
-	req.Service = "alarm_arm_home"
+	req := BaseServiceRequest{
+		Domain:  "alarm_control_panel",
+		Service: "alarm_arm_home",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return acp.conn.WriteMessage(req)
+	return acp.api.Call(req)
 }
 
 // Send the alarm the command for arm night.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (acp AlarmControlPanel) ArmNight(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "alarm_control_panel"
-	req.Service = "alarm_arm_night"
+	req := BaseServiceRequest{
+		Domain:  "alarm_control_panel",
+		Service: "alarm_arm_night",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return acp.conn.WriteMessage(req)
+	return acp.api.Call(req)
 }
 
 // Send the alarm the command for arm vacation.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (acp AlarmControlPanel) ArmVacation(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "alarm_control_panel"
-	req.Service = "alarm_arm_vacation"
+	req := BaseServiceRequest{
+		Domain:  "alarm_control_panel",
+		Service: "alarm_arm_vacation",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return acp.conn.WriteMessage(req)
+	return acp.api.Call(req)
 }
 
 // Send the alarm the command for disarm.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (acp AlarmControlPanel) Disarm(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "alarm_control_panel"
-	req.Service = "alarm_disarm"
+	req := BaseServiceRequest{
+		Domain:  "alarm_control_panel",
+		Service: "alarm_disarm",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return acp.conn.WriteMessage(req)
+	return acp.api.Call(req)
 }
 
 // Send the alarm the command for trigger.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (acp AlarmControlPanel) Trigger(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "alarm_control_panel"
-	req.Service = "alarm_trigger"
+	req := BaseServiceRequest{
+		Domain:  "alarm_control_panel",
+		Service: "alarm_trigger",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return acp.conn.WriteMessage(req)
+	return acp.api.Call(req)
 }
diff --git a/internal/services/climate.go b/internal/services/climate.go
index 74d167d..43c7156 100644
--- a/internal/services/climate.go
+++ b/internal/services/climate.go
@@ -1,32 +1,33 @@
 package services
 
 import (
-	"saml.dev/gome-assistant/internal/websocket"
 	"saml.dev/gome-assistant/types"
 )
 
 /* Structs */
 
 type Climate struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 func (c Climate) SetFanMode(entityId string, fanMode string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "climate"
-	req.Service = "set_fan_mode"
-	req.ServiceData = map[string]any{"fan_mode": fanMode}
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:      "climate",
+		Service:     "set_fan_mode",
+		ServiceData: map[string]any{"fan_mode": fanMode},
+		Target:      Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 func (c Climate) SetTemperature(entityId string, serviceData types.SetTemperatureRequest) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "climate"
-	req.Service = "set_temperature"
-	req.ServiceData = serviceData.ToJSON()
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:      "climate",
+		Service:     "set_temperature",
+		ServiceData: serviceData.ToJSON(),
+		Target:      Entity(entityId),
+	}
+	return c.api.Call(req)
 }
diff --git a/internal/services/cover.go b/internal/services/cover.go
index 4a71893..c0ada6c 100644
--- a/internal/services/cover.go
+++ b/internal/services/cover.go
@@ -1,111 +1,119 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Cover struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 // Close all or specified cover. Takes an entityId.
 func (c Cover) Close(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "close_cover"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "close_cover",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 // Close all or specified cover tilt. Takes an entityId.
 func (c Cover) CloseTilt(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "close_cover_tilt"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "close_cover_tilt",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 // Open all or specified cover. Takes an entityId.
 func (c Cover) Open(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "open_cover"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "open_cover",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 // Open all or specified cover tilt. Takes an entityId.
 func (c Cover) OpenTilt(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "open_cover_tilt"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "open_cover_tilt",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 // Move to specific position all or specified cover. Takes an entityId and an optional
 // map that is translated into service_data.
 func (c Cover) SetPosition(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "set_cover_position"
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "set_cover_position",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return c.conn.WriteMessage(req)
+	return c.api.Call(req)
 }
 
 // Move to specific position all or specified cover tilt. Takes an entityId and an optional
 // map that is translated into service_data.
 func (c Cover) SetTiltPosition(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "set_cover_tilt_position"
+	req := BaseServiceRequest{
+		Target:  Entity(entityId),
+		Domain:  "cover",
+		Service: "set_cover_tilt_position",
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return c.conn.WriteMessage(req)
+	return c.api.Call(req)
 }
 
 // Stop a cover entity. Takes an entityId.
 func (c Cover) Stop(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "stop_cover"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "stop_cover",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 // Stop a cover entity tilt. Takes an entityId.
 func (c Cover) StopTilt(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "stop_cover_tilt"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "stop_cover_tilt",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 // Toggle a cover open/closed. Takes an entityId.
 func (c Cover) Toggle(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "toggle"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "toggle",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
 
 // Toggle a cover tilt open/closed. Takes an entityId.
 func (c Cover) ToggleTilt(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "cover"
-	req.Service = "toggle_cover_tilt"
-
-	return c.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "cover",
+		Service: "toggle_cover_tilt",
+		Target:  Entity(entityId),
+	}
+	return c.api.Call(req)
 }
diff --git a/internal/services/event.go b/internal/services/event.go
index 67ff39d..6747199 100644
--- a/internal/services/event.go
+++ b/internal/services/event.go
@@ -1,20 +1,7 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal"
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 type Event struct {
-	conn *websocket.Conn
-}
-
-// Fire an event
-type FireEventRequest struct {
-	Id        int64          `json:"id"`
-	Type      string         `json:"type"` // always set to "fire_event"
-	EventType string         `json:"event_type"`
-	EventData map[string]any `json:"event_data,omitempty"`
+	api API
 }
 
 /* Public API */
@@ -22,15 +9,8 @@ type FireEventRequest struct {
 // Fire an event. Takes an event type and an optional map that is sent
 // as `event_data`.
 func (e Event) Fire(eventType string, eventData ...map[string]any) error {
-	req := FireEventRequest{
-		Id:   internal.GetId(),
-		Type: "fire_event",
+	if len(eventData) == 0 {
+		return e.api.FireEvent(eventType, nil)
 	}
-
-	req.EventType = eventType
-	if len(eventData) != 0 {
-		req.EventData = eventData[0]
-	}
-
-	return e.conn.WriteMessage(req)
+	return e.api.FireEvent(eventType, eventData[0])
 }
diff --git a/internal/services/homeassistant.go b/internal/services/homeassistant.go
index d888f85..19f93d6 100644
--- a/internal/services/homeassistant.go
+++ b/internal/services/homeassistant.go
@@ -1,43 +1,44 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 type HomeAssistant struct {
-	conn *websocket.Conn
+	api API
 }
 
 // TurnOn a Home Assistant entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (ha *HomeAssistant) TurnOn(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "homeassistant"
-	req.Service = "turn_on"
+	req := BaseServiceRequest{
+		Domain:  "homeassistant",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return ha.conn.WriteMessage(req)
+	return ha.api.Call(req)
 }
 
 // Toggle a Home Assistant entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (ha *HomeAssistant) Toggle(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "homeassistant"
-	req.Service = "toggle"
+	req := BaseServiceRequest{
+		Domain:  "homeassistant",
+		Service: "toggle",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return ha.conn.WriteMessage(req)
+	return ha.api.Call(req)
 }
 
 func (ha *HomeAssistant) TurnOff(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "homeassistant"
-	req.Service = "turn_off"
-
-	return ha.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "homeassistant",
+		Service: "turn_off",
+		Target:  Entity(entityId),
+	}
+	return ha.api.Call(req)
 }
diff --git a/internal/services/input_boolean.go b/internal/services/input_boolean.go
index 788b830..96d4407 100644
--- a/internal/services/input_boolean.go
+++ b/internal/services/input_boolean.go
@@ -1,43 +1,44 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type InputBoolean struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 func (ib InputBoolean) TurnOn(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_boolean"
-	req.Service = "turn_on"
-
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_boolean",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib InputBoolean) Toggle(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_boolean"
-	req.Service = "toggle"
-
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_boolean",
+		Service: "toggle",
+		Target:  Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib InputBoolean) TurnOff(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_boolean"
-	req.Service = "turn_off"
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_boolean",
+		Service: "turn_off",
+		Target:  Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib InputBoolean) Reload() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "input_boolean"
-	req.Service = "reload"
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_boolean",
+		Service: "reload",
+	}
+	return ib.api.Call(req)
 }
diff --git a/internal/services/input_button.go b/internal/services/input_button.go
index 7a20657..3de12db 100644
--- a/internal/services/input_button.go
+++ b/internal/services/input_button.go
@@ -1,28 +1,27 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type InputButton struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 func (ib InputButton) Press(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_button"
-	req.Service = "press"
-
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_button",
+		Service: "press",
+		Target:  Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib InputButton) Reload() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "input_button"
-	req.Service = "reload"
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_button",
+		Service: "reload",
+		Target:  Entity(""),
+	}
+	return ib.api.Call(req)
 }
diff --git a/internal/services/input_datetime.go b/internal/services/input_datetime.go
index 0306838..a83c978 100644
--- a/internal/services/input_datetime.go
+++ b/internal/services/input_datetime.go
@@ -3,32 +3,32 @@ package services
 import (
 	"fmt"
 	"time"
-
-	"saml.dev/gome-assistant/internal/websocket"
 )
 
 /* Structs */
 
 type InputDatetime struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 func (ib InputDatetime) Set(entityId string, value time.Time) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_datetime"
-	req.Service = "set_datetime"
-	req.ServiceData = map[string]any{
-		"timestamp": fmt.Sprint(value.Unix()),
+	req := BaseServiceRequest{
+		Domain:  "input_datetime",
+		Service: "set_datetime",
+		ServiceData: map[string]any{
+			"timestamp": fmt.Sprint(value.Unix()),
+		},
+		Target: Entity(entityId),
 	}
-
-	return ib.conn.WriteMessage(req)
+	return ib.api.Call(req)
 }
 
 func (ib InputDatetime) Reload() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "input_datetime"
-	req.Service = "reload"
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_datetime",
+		Service: "reload",
+	}
+	return ib.api.Call(req)
 }
diff --git a/internal/services/input_number.go b/internal/services/input_number.go
index 596285f..ac12761 100644
--- a/internal/services/input_number.go
+++ b/internal/services/input_number.go
@@ -1,45 +1,45 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type InputNumber struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 func (ib InputNumber) Set(entityId string, value float32) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_number"
-	req.Service = "set_value"
-	req.ServiceData = map[string]any{"value": value}
-
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:      "input_number",
+		Service:     "set_value",
+		ServiceData: map[string]any{"value": value},
+		Target:      Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib InputNumber) Increment(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_number"
-	req.Service = "increment"
-
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_number",
+		Service: "increment",
+		Target:  Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib InputNumber) Decrement(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_number"
-	req.Service = "decrement"
-
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_number",
+		Service: "decrement",
+		Target:  Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib InputNumber) Reload() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "input_number"
-	req.Service = "reload"
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_number",
+		Service: "reload",
+	}
+	return ib.api.Call(req)
 }
diff --git a/internal/services/input_text.go b/internal/services/input_text.go
index ed6789e..1932dc0 100644
--- a/internal/services/input_text.go
+++ b/internal/services/input_text.go
@@ -1,31 +1,29 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type InputText struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 func (ib InputText) Set(entityId string, value string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "input_text"
-	req.Service = "set_value"
-	req.ServiceData = map[string]any{
-		"value": value,
+	req := BaseServiceRequest{
+		Domain:  "input_text",
+		Service: "set_value",
+		ServiceData: map[string]any{
+			"value": value,
+		},
+		Target: Entity(entityId),
 	}
-
-	return ib.conn.WriteMessage(req)
+	return ib.api.Call(req)
 }
 
 func (ib InputText) Reload() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "input_text"
-	req.Service = "reload"
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "input_text",
+		Service: "reload",
+	}
+	return ib.api.Call(req)
 }
diff --git a/internal/services/light.go b/internal/services/light.go
index dedb9b1..e9f7b75 100644
--- a/internal/services/light.go
+++ b/internal/services/light.go
@@ -1,13 +1,9 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Light struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
@@ -15,32 +11,36 @@ type Light struct {
 // TurnOn a light entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (l Light) TurnOn(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "light"
-	req.Service = "turn_on"
+	req := BaseServiceRequest{
+		Domain:  "light",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return l.conn.WriteMessage(req)
+	return l.api.Call(req)
 }
 
 // Toggle a light entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (l Light) Toggle(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "light"
-	req.Service = "toggle"
+	req := BaseServiceRequest{
+		Domain:  "light",
+		Service: "toggle",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return l.conn.WriteMessage(req)
+	return l.api.Call(req)
 }
 
 func (l Light) TurnOff(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "light"
-	req.Service = "turn_off"
-	return l.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "light",
+		Service: "turn_off",
+		Target:  Entity(entityId),
+	}
+	return l.api.Call(req)
 }
diff --git a/internal/services/lock.go b/internal/services/lock.go
index f6e831a..4f80806 100644
--- a/internal/services/lock.go
+++ b/internal/services/lock.go
@@ -1,13 +1,9 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Lock struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
@@ -15,25 +11,27 @@ type Lock struct {
 // Lock a lock entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (l Lock) Lock(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "lock"
-	req.Service = "lock"
+	req := BaseServiceRequest{
+		Domain:  "lock",
+		Service: "lock",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return l.conn.WriteMessage(req)
+	return l.api.Call(req)
 }
 
 // Unlock a lock entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (l Lock) Unlock(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "lock"
-	req.Service = "unlock"
+	req := BaseServiceRequest{
+		Domain:  "lock",
+		Service: "unlock",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return l.conn.WriteMessage(req)
+	return l.api.Call(req)
 }
diff --git a/internal/services/media_player.go b/internal/services/media_player.go
index bc64499..634c1dd 100644
--- a/internal/services/media_player.go
+++ b/internal/services/media_player.go
@@ -1,13 +1,9 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type MediaPlayer struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
@@ -15,255 +11,277 @@ type MediaPlayer struct {
 // Send the media player the command to clear players playlist.
 // Takes an entityId.
 func (mp MediaPlayer) ClearPlaylist(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "clear_playlist"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "clear_playlist",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Group players together. Only works on platforms with support for player groups.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) Join(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "join"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "join",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Send the media player the command for next track.
 // Takes an entityId.
 func (mp MediaPlayer) Next(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "media_next_track"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "media_next_track",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Send the media player the command for pause.
 // Takes an entityId.
 func (mp MediaPlayer) Pause(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "media_pause"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "media_pause",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Send the media player the command for play.
 // Takes an entityId.
 func (mp MediaPlayer) Play(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "media_play"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "media_play",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Toggle media player play/pause state.
 // Takes an entityId.
 func (mp MediaPlayer) PlayPause(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "media_play_pause"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "media_play_pause",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Send the media player the command for previous track.
 // Takes an entityId.
 func (mp MediaPlayer) Previous(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "media_previous_track"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "media_previous_track",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Send the media player the command to seek in current playing media.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) Seek(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "media_seek"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "media_seek",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Send the media player the stop command.
 // Takes an entityId.
 func (mp MediaPlayer) Stop(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "media_stop"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "media_stop",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Send the media player the command for playing media.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) PlayMedia(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "play_media"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "play_media",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Set repeat mode. Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) RepeatSet(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "repeat_set"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "repeat_set",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Send the media player the command to change sound mode.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) SelectSoundMode(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "select_sound_mode"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "select_sound_mode",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Send the media player the command to change input source.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) SelectSource(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "select_source"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "select_source",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Set shuffling state.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) Shuffle(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "shuffle_set"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "shuffle_set",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Toggles a media player power state.
 // Takes an entityId.
 func (mp MediaPlayer) Toggle(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "toggle"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "toggle",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Turn a media player power off.
 // Takes an entityId.
 func (mp MediaPlayer) TurnOff(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "turn_off"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "turn_off",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Turn a media player power on.
 // Takes an entityId.
 func (mp MediaPlayer) TurnOn(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "turn_on"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Unjoin the player from a group. Only works on
 // platforms with support for player groups.
 // Takes an entityId.
 func (mp MediaPlayer) Unjoin(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "unjoin"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "unjoin",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Turn a media player volume down.
 // Takes an entityId.
 func (mp MediaPlayer) VolumeDown(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "volume_down"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "volume_down",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
 
 // Mute a media player's volume.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) VolumeMute(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "volume_mute"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "volume_mute",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Set a media player's volume level.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (mp MediaPlayer) VolumeSet(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "volume_set"
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "volume_set",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return mp.conn.WriteMessage(req)
+	return mp.api.Call(req)
 }
 
 // Turn a media player volume up.
 // Takes an entityId.
 func (mp MediaPlayer) VolumeUp(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "media_player"
-	req.Service = "volume_up"
-
-	return mp.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "media_player",
+		Service: "volume_up",
+		Target:  Entity(entityId),
+	}
+	return mp.api.Call(req)
 }
diff --git a/internal/services/notify.go b/internal/services/notify.go
index 22047fc..66e29c9 100644
--- a/internal/services/notify.go
+++ b/internal/services/notify.go
@@ -1,27 +1,25 @@
 package services
 
 import (
-	"saml.dev/gome-assistant/internal/websocket"
 	"saml.dev/gome-assistant/types"
 )
 
 type Notify struct {
-	conn *websocket.Conn
+	api API
 }
 
 // Notify sends a notification. Takes a types.NotifyRequest.
 func (ha *Notify) Notify(reqData types.NotifyRequest) error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "notify"
-	req.Service = reqData.ServiceName
-
+	req := BaseServiceRequest{
+		Domain:  "notify",
+		Service: reqData.ServiceName,
+	}
 	serviceData := map[string]any{}
 	serviceData["message"] = reqData.Message
 	serviceData["title"] = reqData.Title
 	if reqData.Data != nil {
 		serviceData["data"] = reqData.Data
 	}
-
 	req.ServiceData = serviceData
-	return ha.conn.WriteMessage(req)
+	return ha.api.Call(req)
 }
diff --git a/internal/services/number.go b/internal/services/number.go
index 8a215b2..fa4b4dd 100644
--- a/internal/services/number.go
+++ b/internal/services/number.go
@@ -1,20 +1,17 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 type Number struct {
-	conn *websocket.Conn
+	api API
 }
 
 func (ib Number) SetValue(entityId string, value float32) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "number"
-	req.Service = "set_value"
-	req.ServiceData = map[string]any{"value": value}
-
-	return ib.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:      "number",
+		Service:     "set_value",
+		ServiceData: map[string]any{"value": value},
+		Target:      Entity(entityId),
+	}
+	return ib.api.Call(req)
 }
 
 func (ib Number) MustSetValue(entityId string, value float32) {
diff --git a/internal/services/scene.go b/internal/services/scene.go
index ed729a2..79b29eb 100644
--- a/internal/services/scene.go
+++ b/internal/services/scene.go
@@ -1,60 +1,60 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Scene struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 // Apply a scene. Takes map that is translated into service_data.
 func (s Scene) Apply(serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "scene"
-	req.Service = "apply"
+	req := BaseServiceRequest{
+		Domain:  "scene",
+		Service: "apply",
+		Target:  Entity(""),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return s.conn.WriteMessage(req)
+	return s.api.Call(req)
 }
 
 // Create a scene entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (s Scene) Create(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "scene"
-	req.Service = "create"
+	req := BaseServiceRequest{
+		Domain:  "scene",
+		Service: "create",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return s.conn.WriteMessage(req)
+	return s.api.Call(req)
 }
 
 // Reload the scenes.
 func (s Scene) Reload() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "scene"
-	req.Service = "reload"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "scene",
+		Service: "reload",
+		Target:  Entity(""),
+	}
+	return s.api.Call(req)
 }
 
 // TurnOn a scene entity. Takes an entityId and an optional
 // map that is translated into service_data.
 func (s Scene) TurnOn(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "scene"
-	req.Service = "turn_on"
+	req := BaseServiceRequest{
+		Domain:  "scene",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return s.conn.WriteMessage(req)
+	return s.api.Call(req)
 }
diff --git a/internal/services/script.go b/internal/services/script.go
index dbe6d0f..f8de2d6 100644
--- a/internal/services/script.go
+++ b/internal/services/script.go
@@ -1,49 +1,49 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Script struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 // Reload a script that was created in the HA UI.
 func (s Script) Reload(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "script"
-	req.Service = "reload"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "script",
+		Service: "reload",
+		Target:  Entity(entityId),
+	}
+	return s.api.Call(req)
 }
 
 // Toggle a script that was created in the HA UI.
 func (s Script) Toggle(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "script"
-	req.Service = "toggle"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "script",
+		Service: "toggle",
+		Target:  Entity(entityId),
+	}
+	return s.api.Call(req)
 }
 
 // TurnOff a script that was created in the HA UI.
 func (s Script) TurnOff() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "script"
-	req.Service = "turn_off"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "script",
+		Service: "turn_off",
+		Target:  Entity(""),
+	}
+	return s.api.Call(req)
 }
 
 // TurnOn a script that was created in the HA UI.
 func (s Script) TurnOn(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "script"
-	req.Service = "turn_on"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "script",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
+	return s.api.Call(req)
 }
diff --git a/internal/services/services.go b/internal/services/services.go
index 80bc564..2348ecc 100644
--- a/internal/services/services.go
+++ b/internal/services/services.go
@@ -1,9 +1,11 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal"
-	"saml.dev/gome-assistant/internal/websocket"
-)
+// API is the interface that the individual services use to interact
+// with HomeAssistant.
+type API interface {
+	Call(req BaseServiceRequest) error
+	FireEvent(eventType string, eventData map[string]any) error
+}
 
 func BuildService[
 	T AdaptiveLighting |
@@ -29,29 +31,25 @@ func BuildService[
 		Timer |
 		Vacuum |
 		ZWaveJS,
-](conn *websocket.Conn) *T {
-	return &T{conn: conn}
+](api API) *T {
+	return &T{api: api}
 }
 
 type BaseServiceRequest struct {
 	Id          int64          `json:"id"`
-	RequestType string         `json:"type"` // hardcoded "call_service"
+	RequestType string         `json:"type"` // must be set to "call_service"
 	Domain      string         `json:"domain"`
 	Service     string         `json:"service"`
 	ServiceData map[string]any `json:"service_data,omitempty"`
-	Target      struct {
-		EntityId string `json:"entity_id,omitempty"`
-	} `json:"target,omitempty"`
+	Target      Target         `json:"target,omitempty"`
 }
 
-func NewBaseServiceRequest(entityId string) BaseServiceRequest {
-	id := internal.GetId()
-	bsr := BaseServiceRequest{
-		Id:          id,
-		RequestType: "call_service",
-	}
-	if entityId != "" {
-		bsr.Target.EntityId = entityId
+type Target struct {
+	EntityID string `json:"entity_id,omitempty"`
+}
+
+func Entity(entityID string) Target {
+	return Target{
+		EntityID: entityID,
 	}
-	return bsr
 }
diff --git a/internal/services/switch.go b/internal/services/switch.go
index dee37ee..cde74bc 100644
--- a/internal/services/switch.go
+++ b/internal/services/switch.go
@@ -1,37 +1,36 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Switch struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 func (s Switch) TurnOn(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "switch"
-	req.Service = "turn_on"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "switch",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
+	return s.api.Call(req)
 }
 
 func (s Switch) Toggle(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "switch"
-	req.Service = "toggle"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "switch",
+		Service: "toggle",
+		Target:  Entity(entityId),
+	}
+	return s.api.Call(req)
 }
 
 func (s Switch) TurnOff(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "switch"
-	req.Service = "turn_off"
-
-	return s.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "switch",
+		Service: "turn_off",
+		Target:  Entity(entityId),
+	}
+	return s.api.Call(req)
 }
diff --git a/internal/services/timer.go b/internal/services/timer.go
index 0dfc70d..94b9ef8 100644
--- a/internal/services/timer.go
+++ b/internal/services/timer.go
@@ -1,69 +1,75 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Timer struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 // See https://www.home-assistant.io/integrations/timer/#action-timerstart
 func (t Timer) Start(entityId string, duration string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "timer"
-	req.Service = "start"
-	req.ServiceData = map[string]any{
-		"duration": duration,
+	req := BaseServiceRequest{
+		Domain:  "timer",
+		Service: "start",
+		ServiceData: map[string]any{
+			"duration": duration,
+		},
+		Target: Entity(entityId),
 	}
-
-	return t.conn.WriteMessage(req)
+	return t.api.Call(req)
 }
 
 // See https://www.home-assistant.io/integrations/timer/#action-timerstart
 func (t Timer) Change(entityId string, duration string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "timer"
-	req.Service = "change"
-	req.ServiceData = map[string]any{
-		"duration": duration,
+	req := BaseServiceRequest{
+		Domain:  "timer",
+		Service: "change",
+		ServiceData: map[string]any{
+			"duration": duration,
+		},
+		Target: Entity(entityId),
 	}
-
-	return t.conn.WriteMessage(req)
+	return t.api.Call(req)
 }
 
 // See https://www.home-assistant.io/integrations/timer/#action-timerpause
 func (t Timer) Pause(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "timer"
-	req.Service = "pause"
-	return t.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "timer",
+		Service: "pause",
+		Target:  Entity(entityId),
+	}
+	return t.api.Call(req)
 }
 
 // See https://www.home-assistant.io/integrations/timer/#action-timercancel
 func (t Timer) Cancel() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "timer"
-	req.Service = "cancel"
-	return t.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "timer",
+		Service: "cancel",
+		Target:  Entity(""),
+	}
+	return t.api.Call(req)
 }
 
 // See https://www.home-assistant.io/integrations/timer/#action-timerfinish
 func (t Timer) Finish(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "timer"
-	req.Service = "finish"
-	return t.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "timer",
+		Service: "finish",
+		Target:  Entity(entityId),
+	}
+	return t.api.Call(req)
 }
 
 // See https://www.home-assistant.io/integrations/timer/#action-timerreload
 func (t Timer) Reload() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "timer"
-	req.Service = "reload"
-	return t.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "timer",
+		Service: "reload",
+		Target:  Entity(""),
+	}
+	return t.api.Call(req)
 }
diff --git a/internal/services/tts.go b/internal/services/tts.go
index 60fcf85..7d1156b 100644
--- a/internal/services/tts.go
+++ b/internal/services/tts.go
@@ -1,50 +1,50 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type TTS struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 // Remove all text-to-speech cache files and RAM cache.
 func (tts TTS) ClearCache() error {
-	req := NewBaseServiceRequest("")
-	req.Domain = "tts"
-	req.Service = "clear_cache"
-
-	return tts.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "tts",
+		Service: "clear_cache",
+		Target:  Entity(""),
+	}
+	return tts.api.Call(req)
 }
 
 // Say something using text-to-speech on a media player with cloud.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (tts TTS) CloudSay(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "tts"
-	req.Service = "cloud_say"
+	req := BaseServiceRequest{
+		Domain:  "tts",
+		Service: "cloud_say",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
-
-	return tts.conn.WriteMessage(req)
+	return tts.api.Call(req)
 }
 
 // Say something using text-to-speech on a media player with google_translate.
 // Takes an entityId and an optional
 // map that is translated into service_data.
 func (tts TTS) GoogleTranslateSay(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "tts"
-	req.Service = "google_translate_say"
+	req := BaseServiceRequest{
+		Domain:  "tts",
+		Service: "google_translate_say",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return tts.conn.WriteMessage(req)
+	return tts.api.Call(req)
 }
diff --git a/internal/services/vacuum.go b/internal/services/vacuum.go
index 1d1c136..23dcf8d 100644
--- a/internal/services/vacuum.go
+++ b/internal/services/vacuum.go
@@ -1,13 +1,9 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type Vacuum struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
@@ -15,116 +11,128 @@ type Vacuum struct {
 // Tell the vacuum cleaner to do a spot clean-up.
 // Takes an entityId.
 func (v Vacuum) CleanSpot(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "clean_spot"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "clean_spot",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Locate the vacuum cleaner robot.
 // Takes an entityId.
 func (v Vacuum) Locate(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "locate"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "locate",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Pause the cleaning task.
 // Takes an entityId.
 func (v Vacuum) Pause(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "pause"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "pause",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Tell the vacuum cleaner to return to its dock.
 // Takes an entityId.
 func (v Vacuum) ReturnToBase(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "return_to_base"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "return_to_base",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Send a raw command to the vacuum cleaner. Takes an entityId and an optional
 // map that is translated into service_data.
 func (v Vacuum) SendCommand(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "send_command"
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "send_command",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return v.conn.WriteMessage(req)
+	return v.api.Call(req)
 }
 
 // Set the fan speed of the vacuum cleaner. Takes an entityId and an optional
 // map that is translated into service_data.
 func (v Vacuum) SetFanSpeed(entityId string, serviceData ...map[string]any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "set_fan_speed"
-
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "set_fan_speed",
+		Target:  Entity(entityId),
+	}
 	if len(serviceData) != 0 {
 		req.ServiceData = serviceData[0]
 	}
 
-	return v.conn.WriteMessage(req)
+	return v.api.Call(req)
 }
 
 // Start or resume the cleaning task.
 // Takes an entityId.
 func (v Vacuum) Start(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "start"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "start",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Start, pause, or resume the cleaning task.
 // Takes an entityId.
 func (v Vacuum) StartPause(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "start_pause"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "start_pause",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Stop the current cleaning task.
 // Takes an entityId.
 func (v Vacuum) Stop(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "stop"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "stop",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Stop the current cleaning task and return to home.
 // Takes an entityId.
 func (v Vacuum) TurnOff(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "turn_off"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "turn_off",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
 
 // Start a new cleaning task.
 // Takes an entityId.
 func (v Vacuum) TurnOn(entityId string) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "vacuum"
-	req.Service = "turn_on"
-
-	return v.conn.WriteMessage(req)
+	req := BaseServiceRequest{
+		Domain:  "vacuum",
+		Service: "turn_on",
+		Target:  Entity(entityId),
+	}
+	return v.api.Call(req)
 }
diff --git a/internal/services/zwavejs.go b/internal/services/zwavejs.go
index 9baf96c..c5255d9 100644
--- a/internal/services/zwavejs.go
+++ b/internal/services/zwavejs.go
@@ -1,26 +1,23 @@
 package services
 
-import (
-	"saml.dev/gome-assistant/internal/websocket"
-)
-
 /* Structs */
 
 type ZWaveJS struct {
-	conn *websocket.Conn
+	api API
 }
 
 /* Public API */
 
 // ZWaveJS bulk_set_partial_config_parameters service.
 func (zw ZWaveJS) BulkSetPartialConfigParam(entityId string, parameter int, value any) error {
-	req := NewBaseServiceRequest(entityId)
-	req.Domain = "zwave_js"
-	req.Service = "bulk_set_partial_config_parameters"
-	req.ServiceData = map[string]any{
-		"parameter": parameter,
-		"value":     value,
+	req := BaseServiceRequest{
+		Domain:  "zwave_js",
+		Service: "bulk_set_partial_config_parameters",
+		ServiceData: map[string]any{
+			"parameter": parameter,
+			"value":     value,
+		},
+		Target: Entity(entityId),
 	}
-
-	return zw.conn.WriteMessage(req)
+	return zw.api.Call(req)
 }
diff --git a/internal/websocket/locked_conn.go b/internal/websocket/locked_conn.go
new file mode 100644
index 0000000..8557b71
--- /dev/null
+++ b/internal/websocket/locked_conn.go
@@ -0,0 +1,40 @@
+package websocket
+
+import "fmt"
+
+// LockedConn represents a `Conn` that is currently locked for
+// writing. It is created within [Conn.Send] for the use of that
+// method's callback function.
+type LockedConn interface {
+	// NextMessageID returns the next unused id to be used in a websocket
+	// message. The IDs so generated must be used in order, while the
+	// `LockedConn` is still active.
+	NextMessageID() int64
+
+	// SendMessage sends the specified message over the websocket
+	// connection. `msg` must be JSON-serializable and have the
+	// correct format and a unique, monotonically-increasing ID, which
+	// should be generated using `NextMessageID()` and used in order.
+	SendMessage(msg any) error
+}
+
+// lockedConn is a `LockedConn` view of a `Conn`, to be used
+// only for a finite time when the connection is locked.
+type lockedConn struct {
+	conn *Conn
+}
+
+// NextMessageID implements [LockedConn.NextMessageID].
+func (lc lockedConn) NextMessageID() int64 {
+	lc.conn.lastMessageID++
+	return lc.conn.lastMessageID
+}
+
+// SendMessage implements [LockedConn.SendMessage].
+func (lc lockedConn) SendMessage(msg any) error {
+	if err := lc.conn.conn.WriteJSON(msg); err != nil {
+		return fmt.Errorf("sending websocket message to server: %w", err)
+	}
+
+	return nil
+}
diff --git a/internal/websocket/send.go b/internal/websocket/send.go
new file mode 100644
index 0000000..e892427
--- /dev/null
+++ b/internal/websocket/send.go
@@ -0,0 +1,31 @@
+package websocket
+
+// Messager is called by `Send()` while holding the `writeMutex`. It
+// can send one or more messages by (for each message) allocating an
+// ID using `lc.NextMessageID()` then sending the message using
+// `lc.SendMessage()`. The `LockedConn` should only be used while the
+// callback is running.
+type Messager func(lc LockedConn) error
+
+// Send is the primary way to write a message over the websocket
+// interface. Since these messages require monotonically-increasing ID
+// numbers, the work from allocating a new ID number through sending
+// the message has to be done under the `writeMutex`. This is done by
+// passing this function a `Messager`, which is invoked while holding
+// the lock.
+//
+// Usage:
+//
+//	msg := NewFooMessage{…}
+//	err := conn.Send(func(lc LockedConn) error {
+//		id := lc.NextMessageID()
+//		// …do anything else that needs to be done with `id`…
+//		msg.ID = id
+//		return lc.SendMessage(msg)
+//	})
+func (conn *Conn) Send(msgr Messager) error {
+	conn.writeLock.Lock()
+	defer conn.writeLock.Unlock()
+
+	return msgr(lockedConn{conn: conn})
+}
diff --git a/internal/websocket/websocket.go b/internal/websocket/websocket.go
index 3b1376e..b91445f 100644
--- a/internal/websocket/websocket.go
+++ b/internal/websocket/websocket.go
@@ -14,8 +14,6 @@ import (
 	"sync"
 
 	"github.com/gorilla/websocket"
-
-	"saml.dev/gome-assistant/internal"
 )
 
 var ErrInvalidToken = errors.New("invalid authentication token")
@@ -26,15 +24,9 @@ type AuthMessage struct {
 }
 
 type Conn struct {
-	conn  *websocket.Conn
-	mutex sync.Mutex
-}
-
-func (conn *Conn) WriteMessage(msg any) error {
-	conn.mutex.Lock()
-	defer conn.mutex.Unlock()
-
-	return conn.conn.WriteJSON(msg)
+	conn          *websocket.Conn
+	writeLock     sync.Mutex
+	lastMessageID int64
 }
 
 func (conn *Conn) readMessage() ([]byte, error) {
@@ -135,28 +127,45 @@ type SubEvent struct {
 	EventType string `json:"event_type"`
 }
 
-func SubscribeToStateChangedEvents(ctx context.Context, id int64, conn *Conn) {
-	SubscribeToEventType(ctx, "state_changed", conn, id)
+// Subscription represents a websocket-level subscription to a
+// particular message ID.
+type Subscription struct {
+	id int64
 }
 
-func SubscribeToEventType(ctx context.Context, eventType string, conn *Conn, id ...int64) {
-	var finalId int64
-	if len(id) == 0 {
-		finalId = internal.GetId()
-	} else {
-		finalId = id[0]
-	}
-	e := SubEvent{
-		Id:        finalId,
-		Type:      "subscribe_events",
-		EventType: eventType,
-	}
-	err := conn.WriteMessage(e)
+func (sub Subscription) ID() int64 {
+	return sub.id
+}
+
+func SubscribeToStateChangedEvents(conn *Conn) Subscription {
+	return SubscribeToEventType("state_changed", conn)
+}
+
+func SubscribeToEventType(eventType string, conn *Conn) Subscription {
+	var id int64
+	err := conn.Send(
+		func(lc LockedConn) error {
+			id = lc.NextMessageID()
+			e := SubEvent{
+				Id:        id,
+				Type:      "subscribe_events",
+				EventType: eventType,
+			}
+
+			if err := lc.SendMessage(e); err != nil {
+				return fmt.Errorf("error writing to websocket: %w", err)
+			}
+			// m, _ := ReadMessage(ctx, conn)
+			// log.Default().Println(string(m))
+
+			return nil
+		},
+	)
+
 	if err != nil {
-		wrappedErr := fmt.Errorf("error writing to websocket: %w", err)
-		slog.Error(wrappedErr.Error())
-		panic(wrappedErr)
+		slog.Error(err.Error())
+		panic(err)
 	}
-	// m, _ := ReadMessage(ctx, conn)
-	// log.Default().Println(string(m))
+
+	return Subscription{id}
 }
diff --git a/interval.go b/interval.go
index 5458966..2d31949 100644
--- a/interval.go
+++ b/interval.go
@@ -149,7 +149,7 @@ func (sb intervalBuilderEnd) Build() Interval {
 
 // run invokes `i.maybeRunCallback()` based on its configured
 // frequency.
-func (i Interval) run(ctx context.Context, a *App) {
+func (i Interval) run(ctx context.Context, app *App) {
 	// Create a new, but stopped, timer for sleeping on:
 	timer := time.NewTimer(1 * time.Hour)
 	if !timer.Stop() {
@@ -167,12 +167,12 @@ func (i Interval) run(ctx context.Context, a *App) {
 			}
 		}
 
-		i.maybeRunCallback(a)
+		i.maybeRunCallback(app)
 		i.nextRunTime = i.nextRunTime.Add(i.frequency)
 	}
 }
 
-func (i Interval) maybeRunCallback(a *App) {
+func (i Interval) maybeRunCallback(app *App) {
 	if c := checkStartEndTime(i.startTime /* isStart = */, true); c.fail {
 		return
 	}
@@ -185,11 +185,11 @@ func (i Interval) maybeRunCallback(a *App) {
 	if c := checkExceptionRanges(i.exceptionRanges); c.fail {
 		return
 	}
-	if c := checkEnabledEntity(a.state, i.enabledEntities); c.fail {
+	if c := checkEnabledEntity(app.state, i.enabledEntities); c.fail {
 		return
 	}
-	if c := checkDisabledEntity(a.state, i.disabledEntities); c.fail {
+	if c := checkDisabledEntity(app.state, i.disabledEntities); c.fail {
 		return
 	}
-	go i.callback(a.service, a.state)
+	go i.callback(app.service, app.state)
 }
diff --git a/schedule.go b/schedule.go
index 979c2f4..2113893 100644
--- a/schedule.go
+++ b/schedule.go
@@ -155,7 +155,7 @@ func (sb scheduleBuilderEnd) Build() DailySchedule {
 
 // run invokes `s.maybeRunCallback()` based on its configured
 // schedule. Terminate when `ctx` is canceled.
-func (s DailySchedule) run(ctx context.Context, a *App) {
+func (s DailySchedule) run(ctx context.Context, app *App) {
 	// Create a new, but stopped, timer for sleeping on:
 	timer := time.NewTimer(1 * time.Hour)
 	if !timer.Stop() {
@@ -175,37 +175,37 @@ func (s DailySchedule) run(ctx context.Context, a *App) {
 			}
 		}
 
-		s.maybeRunCallback(a)
-		s.updateNextRunTime(a)
+		s.maybeRunCallback(app)
+		s.updateNextRunTime(app)
 	}
 }
 
-func (s DailySchedule) maybeRunCallback(a *App) {
+func (s DailySchedule) maybeRunCallback(app *App) {
 	if c := checkExceptionDates(s.exceptionDates); c.fail {
 		return
 	}
 	if c := checkAllowlistDates(s.allowlistDates); c.fail {
 		return
 	}
-	if c := checkEnabledEntity(a.state, s.enabledEntities); c.fail {
+	if c := checkEnabledEntity(app.state, s.enabledEntities); c.fail {
 		return
 	}
-	if c := checkDisabledEntity(a.state, s.disabledEntities); c.fail {
+	if c := checkDisabledEntity(app.state, s.disabledEntities); c.fail {
 		return
 	}
-	go s.callback(a.service, a.state)
+	go s.callback(app.service, app.state)
 }
 
 // updateNextRunTime updates `s.nextRunTime` to the next time that `s`
 // should run.
-func (s DailySchedule) updateNextRunTime(a *App) {
+func (s DailySchedule) updateNextRunTime(app *App) {
 	if s.isSunrise || s.isSunset {
 		var nextSunTime carbon.Carbon
 		// "0s" is default value
 		if s.sunOffset != "0s" {
-			nextSunTime = getNextSunRiseOrSet(a, s.isSunrise, s.sunOffset)
+			nextSunTime = getNextSunRiseOrSet(app, s.isSunrise, s.sunOffset)
 		} else {
-			nextSunTime = getNextSunRiseOrSet(a, s.isSunrise)
+			nextSunTime = getNextSunRiseOrSet(app, s.isSunrise)
 		}
 
 		s.nextRunTime = nextSunTime.Carbon2Time()
diff --git a/service.go b/service.go
index 049106b..cf973dc 100644
--- a/service.go
+++ b/service.go
@@ -2,7 +2,6 @@ package gomeassistant
 
 import (
 	"saml.dev/gome-assistant/internal/services"
-	"saml.dev/gome-assistant/internal/websocket"
 )
 
 type Service struct {
@@ -31,30 +30,30 @@ type Service struct {
 	ZWaveJS           *services.ZWaveJS
 }
 
-func newService(conn *websocket.Conn) *Service {
+func newService(app *App) *Service {
 	return &Service{
-		AdaptiveLighting:  services.BuildService[services.AdaptiveLighting](conn),
-		AlarmControlPanel: services.BuildService[services.AlarmControlPanel](conn),
-		Climate:           services.BuildService[services.Climate](conn),
-		Cover:             services.BuildService[services.Cover](conn),
-		Light:             services.BuildService[services.Light](conn),
-		HomeAssistant:     services.BuildService[services.HomeAssistant](conn),
-		Lock:              services.BuildService[services.Lock](conn),
-		MediaPlayer:       services.BuildService[services.MediaPlayer](conn),
-		Switch:            services.BuildService[services.Switch](conn),
-		InputBoolean:      services.BuildService[services.InputBoolean](conn),
-		InputButton:       services.BuildService[services.InputButton](conn),
-		InputText:         services.BuildService[services.InputText](conn),
-		InputDatetime:     services.BuildService[services.InputDatetime](conn),
-		InputNumber:       services.BuildService[services.InputNumber](conn),
-		Event:             services.BuildService[services.Event](conn),
-		Notify:            services.BuildService[services.Notify](conn),
-		Number:            services.BuildService[services.Number](conn),
-		Scene:             services.BuildService[services.Scene](conn),
-		Script:            services.BuildService[services.Script](conn),
-		Timer:             services.BuildService[services.Timer](conn),
-		TTS:               services.BuildService[services.TTS](conn),
-		Vacuum:            services.BuildService[services.Vacuum](conn),
-		ZWaveJS:           services.BuildService[services.ZWaveJS](conn),
+		AdaptiveLighting:  services.BuildService[services.AdaptiveLighting](app),
+		AlarmControlPanel: services.BuildService[services.AlarmControlPanel](app),
+		Climate:           services.BuildService[services.Climate](app),
+		Cover:             services.BuildService[services.Cover](app),
+		Light:             services.BuildService[services.Light](app),
+		HomeAssistant:     services.BuildService[services.HomeAssistant](app),
+		Lock:              services.BuildService[services.Lock](app),
+		MediaPlayer:       services.BuildService[services.MediaPlayer](app),
+		Switch:            services.BuildService[services.Switch](app),
+		InputBoolean:      services.BuildService[services.InputBoolean](app),
+		InputButton:       services.BuildService[services.InputButton](app),
+		InputText:         services.BuildService[services.InputText](app),
+		InputDatetime:     services.BuildService[services.InputDatetime](app),
+		InputNumber:       services.BuildService[services.InputNumber](app),
+		Event:             services.BuildService[services.Event](app),
+		Notify:            services.BuildService[services.Notify](app),
+		Number:            services.BuildService[services.Number](app),
+		Scene:             services.BuildService[services.Scene](app),
+		Script:            services.BuildService[services.Script](app),
+		Timer:             services.BuildService[services.Timer](app),
+		TTS:               services.BuildService[services.TTS](app),
+		Vacuum:            services.BuildService[services.Vacuum](app),
+		ZWaveJS:           services.BuildService[services.ZWaveJS](app),
 	}
 }