diff --git a/upnp/devices/device.go b/upnp/devices/device.go
new file mode 100644
index 00000000..a71b43df
--- /dev/null
+++ b/upnp/devices/device.go
@@ -0,0 +1,16 @@
+package devices
+
+type Device struct {
+	deviceType       string
+	friendlyName     string
+	manufacturer     string
+	manufacturerURL  string
+	modelDescription string
+	modelName        string
+	modelNumber      string
+	modelURL         string
+	serialNumber     string
+	specVersion      string
+	presentationURL  string
+	UDN              string
+}
diff --git a/upnp/devices/mediarenderer/AVTransport/avtransport.go b/upnp/devices/mediarenderer/AVTransport/avtransport.go
new file mode 100644
index 00000000..48be64c7
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/avtransport.go
@@ -0,0 +1,17 @@
+package mediarenderer
+
+import "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services"
+
+var AVTransport = func() *services.Service {
+	svc := services.NewService("AVTransport")
+
+	svc.AddVariable(AVTransportURI)
+	svc.AddVariable(AVTransportURIMetaData)
+	svc.AddVariable(CurrentTrackDuration)
+	svc.AddVariable(SeekMode)
+	svc.AddVariable(TransportPlaySpeed)
+	svc.AddVariable(TransportState)
+	svc.AddVariable(TransportStatus)
+
+	return svc
+}()
diff --git a/upnp/devices/mediarenderer/AVTransport/sv_AVTransportURI.go b/upnp/devices/mediarenderer/AVTransport/sv_AVTransportURI.go
new file mode 100644
index 00000000..074ceba7
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/sv_AVTransportURI.go
@@ -0,0 +1,10 @@
+package mediarenderer
+
+import sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+
+var AVTransportURI = func() *sv.StateVariable {
+
+	ts := sv.StateType_String.NewStateValue("AVTransportURI")
+
+	return ts
+}()
diff --git a/upnp/devices/mediarenderer/AVTransport/sv_AVTransportURIMetaData.go b/upnp/devices/mediarenderer/AVTransport/sv_AVTransportURIMetaData.go
new file mode 100644
index 00000000..7650e1de
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/sv_AVTransportURIMetaData.go
@@ -0,0 +1,10 @@
+package mediarenderer
+
+import sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+
+var AVTransportURIMetaData = func() *sv.StateVariable {
+
+	ts := sv.StateType_String.NewStateValue("AVTransportURIMetaData")
+
+	return ts
+}()
diff --git a/upnp/devices/mediarenderer/AVTransport/sv_CurrentTrackDuration.go b/upnp/devices/mediarenderer/AVTransport/sv_CurrentTrackDuration.go
new file mode 100644
index 00000000..93ab9216
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/sv_CurrentTrackDuration.go
@@ -0,0 +1,10 @@
+package mediarenderer
+
+import sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+
+var CurrentTrackDuration = func() *sv.StateVariable {
+
+	ts := sv.StateType_String.NewStateValue("CurrentTrackDuration")
+
+	return ts
+}()
diff --git a/upnp/devices/mediarenderer/AVTransport/sv_SeekMode.go b/upnp/devices/mediarenderer/AVTransport/sv_SeekMode.go
new file mode 100644
index 00000000..4e7b6a0a
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/sv_SeekMode.go
@@ -0,0 +1,10 @@
+package mediarenderer
+
+import sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+
+var SeekMode = func() *sv.StateVariable {
+
+	ts := sv.StateType_String.NewStateValue("SeekMode")
+
+	return ts
+}()
diff --git a/upnp/devices/mediarenderer/AVTransport/sv_TransportPlaySpeed.go b/upnp/devices/mediarenderer/AVTransport/sv_TransportPlaySpeed.go
new file mode 100644
index 00000000..4313a814
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/sv_TransportPlaySpeed.go
@@ -0,0 +1,10 @@
+package mediarenderer
+
+import sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+
+var TransportPlaySpeed = func() *sv.StateVariable {
+
+	ts := sv.StateType_String.NewStateValue("TransportPlaySpeed")
+
+	return ts
+}()
diff --git a/upnp/devices/mediarenderer/AVTransport/sv_TransportState.go b/upnp/devices/mediarenderer/AVTransport/sv_TransportState.go
new file mode 100644
index 00000000..1f42648a
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/sv_TransportState.go
@@ -0,0 +1,20 @@
+package mediarenderer
+
+import sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+
+var TransportState = func() *sv.StateVariable {
+
+	ts := sv.StateType_String.NewStateValue("TransportState")
+
+	ts.SetAllowedValues(
+		"STOPPED",
+		"PLAYING",
+		"PAUSED_PLAYBACK",
+		"TRANSITIONING",
+		"NO_MEDIA_PRESENT",
+	)
+
+	ts.SetSendingEvents()
+
+	return ts
+}()
diff --git a/upnp/devices/mediarenderer/AVTransport/sv_TransportStatus.go b/upnp/devices/mediarenderer/AVTransport/sv_TransportStatus.go
new file mode 100644
index 00000000..c3c4fefd
--- /dev/null
+++ b/upnp/devices/mediarenderer/AVTransport/sv_TransportStatus.go
@@ -0,0 +1,17 @@
+package mediarenderer
+
+import sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+
+var TransportStatus = func() *sv.StateVariable {
+
+	ts := sv.StateType_String.NewStateValue("TransportStatus")
+
+	ts.SetAllowedValues(
+		"OK",
+		"ERROR_OCCURRED",
+	)
+
+	ts.SetSendingEvents()
+
+	return ts
+}()
diff --git a/upnp/devices/mediarenderer/ConnectionManager/sv_SourceProtocolInfo.go b/upnp/devices/mediarenderer/ConnectionManager/sv_SourceProtocolInfo.go
new file mode 100644
index 00000000..61eae595
--- /dev/null
+++ b/upnp/devices/mediarenderer/ConnectionManager/sv_SourceProtocolInfo.go
@@ -0,0 +1 @@
+package connectionmanager
diff --git a/upnp/devices/services/actions/action.go b/upnp/devices/services/actions/action.go
new file mode 100644
index 00000000..6057a5f6
--- /dev/null
+++ b/upnp/devices/services/actions/action.go
@@ -0,0 +1,39 @@
+package actions
+
+import "github.com/beevik/etree"
+
+type Action struct {
+	name string
+
+	arguments ArgumentSet
+}
+
+func NewAction(name string) *Action {
+	ac := &Action{
+		name: name,
+	}
+
+	return ac
+}
+
+func (a *Action) Name() string {
+	return a.name
+}
+
+func (a *Action) TypeID() string {
+	return "Action"
+}
+
+func (a *Action) AddArgument(arg *Argument) {
+	a.arguments.Insert(arg)
+}
+
+func (a *Action) ToXMLElement() *etree.Element {
+	elem := etree.NewElement("action")
+
+	name := elem.CreateElement("name")
+	name.SetText(a.Name())
+
+	elem.AddChild(a.arguments.ToXMLElement())
+	return elem
+}
diff --git a/upnp/devices/services/actions/actionset.go b/upnp/devices/services/actions/actionset.go
new file mode 100644
index 00000000..e0d350f3
--- /dev/null
+++ b/upnp/devices/services/actions/actionset.go
@@ -0,0 +1,32 @@
+package actions
+
+import (
+	"iter"
+
+	"gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/objectstore"
+	"github.com/beevik/etree"
+)
+
+type ActionSet objectstore.ObjectSet[*Action]
+
+func (m *ActionSet) Insert(obj *Action) {
+	(*objectstore.ObjectSet[*Action])(m).Insert(obj)
+}
+
+func (set *ActionSet) Contains(obj *Action) bool {
+	return (*objectstore.ObjectSet[*Action])(set).Contains(obj)
+}
+
+func (m *ActionSet) All() iter.Seq[*Action] {
+	return (*objectstore.ObjectSet[*Action])(m).All()
+}
+
+func (m *ActionSet) ToXMLElement() *etree.Element {
+	elem := etree.NewElement("ActionList")
+
+	for sv := range m.All() {
+		elem.AddChild(sv.ToXMLElement())
+	}
+
+	return elem
+}
diff --git a/upnp/devices/services/actions/argument.go b/upnp/devices/services/actions/argument.go
new file mode 100644
index 00000000..4aaaa8c3
--- /dev/null
+++ b/upnp/devices/services/actions/argument.go
@@ -0,0 +1,100 @@
+package actions
+
+import (
+	"gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+	"github.com/beevik/etree"
+)
+
+type Argument struct {
+	name           string
+	statevariables *statevariables.StateVariable
+	in             bool
+	out            bool
+}
+
+func newArgument(name string, statevariable *statevariables.StateVariable) *Argument {
+	arg := &Argument{
+		name:           name,
+		statevariables: statevariable,
+	}
+	return arg
+}
+
+func NewInArgument(name string, statevariable *statevariables.StateVariable) *Argument {
+	arg := newArgument(name, statevariable)
+	arg.in = true
+	return arg
+}
+
+func NewOutArgument(name string, statevariable *statevariables.StateVariable) *Argument {
+	arg := newArgument(name, statevariable)
+	arg.out = true
+	return arg
+}
+
+func NewInOutArgument(name string, statevariable *statevariables.StateVariable) *Argument {
+	arg := newArgument(name, statevariable)
+	arg.in = true
+	arg.out = true
+	return arg
+}
+
+func (a *Argument) Name() string {
+	return a.name
+}
+
+func (sv Argument) TypeID() string {
+	return "Argument"
+}
+
+func (a *Argument) StateVariable() *statevariables.StateVariable {
+	return a.statevariables
+}
+
+func (a *Argument) IsIn() bool {
+	return a.in
+}
+
+func (a *Argument) IsOut() bool {
+	return a.out
+}
+
+func (a *Argument) ToXMLElement() *etree.Element {
+	var elem, arg *etree.Element
+
+	if a.IsIn() && a.IsOut() {
+		elem = etree.NewElement("")
+		arg = elem.CreateElement("argument")
+	} else {
+		elem = etree.NewElement("argument")
+		arg = elem
+	}
+
+	if a.IsIn() {
+		name := arg.CreateElement("name")
+		name.SetText(a.Name())
+
+		direction := arg.CreateElement("direction")
+		direction.SetText("in")
+
+		relatedStateVariable := arg.CreateElement("relatedStateVariable")
+		relatedStateVariable.SetText(a.StateVariable().Name())
+	}
+
+	if a.IsIn() && a.IsOut() {
+		arg = elem.CreateElement("argument")
+	}
+
+	if a.IsOut() {
+		name := arg.CreateElement("name")
+		name.SetText(a.Name())
+
+		direction := arg.CreateElement("direction")
+		direction.SetText("out")
+
+		relatedStateVariable := arg.CreateElement("relatedStateVariable")
+		relatedStateVariable.SetText(a.StateVariable().Name())
+	}
+
+	return elem
+}
diff --git a/upnp/devices/services/actions/argumentset.go b/upnp/devices/services/actions/argumentset.go
new file mode 100644
index 00000000..967037c0
--- /dev/null
+++ b/upnp/devices/services/actions/argumentset.go
@@ -0,0 +1,32 @@
+package actions
+
+import (
+	"iter"
+
+	"gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/objectstore"
+	"github.com/beevik/etree"
+)
+
+type ArgumentSet objectstore.ObjectSet[*Argument]
+
+func (m *ArgumentSet) Insert(obj *Argument) {
+	(*objectstore.ObjectSet[*Argument])(m).Insert(obj)
+}
+
+func (set *ArgumentSet) Contains(obj *Argument) bool {
+	return (*objectstore.ObjectSet[*Argument])(set).Contains(obj)
+}
+
+func (m *ArgumentSet) All() iter.Seq[*Argument] {
+	return (*objectstore.ObjectSet[*Argument])(m).All()
+}
+
+func (m *ArgumentSet) ToXMLElement() *etree.Element {
+	elem := etree.NewElement("argumentList")
+
+	for sv := range m.All() {
+		elem.AddChild(sv.ToXMLElement())
+	}
+
+	return elem
+}
diff --git a/upnp/devices/services/service.go b/upnp/devices/services/service.go
new file mode 100644
index 00000000..3a3fddc2
--- /dev/null
+++ b/upnp/devices/services/service.go
@@ -0,0 +1,129 @@
+package services
+
+import (
+	"fmt"
+	"iter"
+
+	"github.com/beevik/etree"
+
+	"gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/actions"
+	sv "gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/devices/services/statevariables"
+)
+
+type Service struct {
+	name       string
+	identifier string
+	version    int
+
+	controlURL  string
+	eventSubURL string
+	scpdURL     string
+
+	actions    actions.ActionSet
+	stateTable sv.StateVariableSet
+}
+
+func NewService(name string) *Service {
+	svc := &Service{
+		name:        name,
+		identifier:  name,
+		controlURL:  "/service/" + name + "/control",
+		eventSubURL: "/service/" + name + "/event",
+		scpdURL:     "/service/" + name + "/desc.xml",
+		version:     1,
+	}
+
+	return svc
+}
+
+func (svc *Service) Name() string {
+	return svc.name
+}
+
+func (svc *Service) TypeID() string {
+	return "Service"
+}
+
+func (svc *Service) ServiceType() string {
+	return fmt.Sprintf("urn:schemas-upnp-org:service:%s:%d", svc.name, svc.version)
+}
+
+func (svc *Service) ServiceId() string {
+	return fmt.Sprintf("urn:upnp-org:serviceId:%s", svc.identifier)
+}
+
+func (svc *Service) SetIdentifier(id string) {
+	svc.identifier = id
+}
+
+func (svc *Service) ControlURL() string {
+	return svc.controlURL
+}
+
+func (svc *Service) SetControlURL(url string) {
+	svc.controlURL = url
+}
+
+func (svc *Service) EventSubURL() string {
+	return svc.eventSubURL
+}
+
+func (svc *Service) SetEventSubURL(url string) {
+	svc.eventSubURL = url
+}
+
+func (svc *Service) SCPDURL() string {
+	return svc.scpdURL
+}
+
+func (svc *Service) SetSCPDURL(url string) {
+	svc.scpdURL = url
+}
+
+func (svc *Service) SetVersion(version int) error {
+	if version < 1 {
+		return fmt.Errorf("%s", "version must be greater than or equal to 1")
+	}
+	svc.version = version
+	return nil
+}
+
+func (svc *Service) Version() int {
+	return svc.version
+}
+
+func (svc *Service) AddVariable(sv *sv.StateVariable) {
+	svc.stateTable.Insert(sv)
+}
+
+func (svc *Service) ContaintsVariable(sv *sv.StateVariable) bool {
+	return svc.stateTable.Contains(sv)
+}
+
+func (svc *Service) Variables() iter.Seq[*sv.StateVariable] {
+	return svc.stateTable.All()
+}
+
+func (svc *Service) AddAction(ac *actions.Action) {
+}
+
+func (svc *Service) ToXMLElement() *etree.Element {
+	elem := etree.NewElement("service")
+
+	st := elem.CreateElement("serviceType")
+	st.SetText(svc.ServiceType())
+
+	sid := elem.CreateElement("serviceId")
+	sid.SetText(svc.ServiceId())
+
+	spcd := elem.CreateElement("SCPDURL")
+	spcd.SetText(svc.SCPDURL())
+
+	ctrl := elem.CreateElement("controlURL")
+	ctrl.SetText(svc.ControlURL())
+
+	event := elem.CreateElement("eventSubURL")
+	event.SetText(svc.EventSubURL())
+
+	return elem
+}
diff --git a/upnp/devices/services/serviceset.go b/upnp/devices/services/serviceset.go
new file mode 100644
index 00000000..79464ee1
--- /dev/null
+++ b/upnp/devices/services/serviceset.go
@@ -0,0 +1,32 @@
+package services
+
+import (
+	"iter"
+
+	"gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/objectstore"
+	"github.com/beevik/etree"
+)
+
+type ServiceSet objectstore.ObjectSet[*Service]
+
+func (m *ServiceSet) Insert(obj *Service) {
+	(*objectstore.ObjectSet[*Service])(m).Insert(obj)
+}
+
+func (set *ServiceSet) Contains(obj *Service) bool {
+	return (*objectstore.ObjectSet[*Service])(set).Contains(obj)
+}
+
+func (m *ServiceSet) All() iter.Seq[*Service] {
+	return (*objectstore.ObjectSet[*Service])(m).All()
+}
+
+func (m *ServiceSet) ToXMLElement() *etree.Element {
+	elem := etree.NewElement("ServiceList")
+
+	for sv := range m.All() {
+		elem.AddChild(sv.ToXMLElement())
+	}
+
+	return elem
+}
diff --git a/upnp/statevariables/statevalueinstance.go b/upnp/devices/services/statevariables/statevalueinstance.go
similarity index 100%
rename from upnp/statevariables/statevalueinstance.go
rename to upnp/devices/services/statevariables/statevalueinstance.go
diff --git a/upnp/statevariables/statevariable.go b/upnp/devices/services/statevariables/statevariable.go
similarity index 99%
rename from upnp/statevariables/statevariable.go
rename to upnp/devices/services/statevariables/statevariable.go
index 38c216df..8c21a980 100644
--- a/upnp/statevariables/statevariable.go
+++ b/upnp/devices/services/statevariables/statevariable.go
@@ -49,6 +49,10 @@ func (sv StateVariable) Name() string {
 	return sv.name
 }
 
+func (sv StateVariable) TypeID() string {
+	return "StateVariable"
+}
+
 // Type returns the UPnP data type of the state variable.
 func (state *StateVariable) Type() StateVarType {
 	return state.valueType
@@ -431,7 +435,6 @@ func (state *StateVariable) NewInstance() *StateVarInstance {
 func (sv *StateVariable) ToXMLElement() *etree.Element {
 	// Create root <stateVariable> element
 	elem := etree.NewElement("stateVariable")
-	elem.CreateAttr("name", sv.name)
 
 	// Add sendEvents attribute (UPnP eventing capability)
 	if sv.sendEvents {
@@ -440,6 +443,9 @@ func (sv *StateVariable) ToXMLElement() *etree.Element {
 		elem.CreateAttr("sendEvents", "no") // Disable event notifications
 	}
 
+	name := elem.CreateElement("name")
+	name.SetText(sv.Name())
+
 	// Add data type element
 	dataType := elem.CreateElement("dataType")
 	dataType.SetText(sv.valueType.String()) // Set UPnP type name (e.g., "ui1", "boolean")
diff --git a/upnp/statevariables/statevariable_TransferStatus.go b/upnp/devices/services/statevariables/statevariable_TransferStatus.go
similarity index 100%
rename from upnp/statevariables/statevariable_TransferStatus.go
rename to upnp/devices/services/statevariables/statevariable_TransferStatus.go
diff --git a/upnp/statevariables/statevariable_Volume.go b/upnp/devices/services/statevariables/statevariable_Volume.go
similarity index 100%
rename from upnp/statevariables/statevariable_Volume.go
rename to upnp/devices/services/statevariables/statevariable_Volume.go
diff --git a/upnp/statevariables/statevariable_arithm.go b/upnp/devices/services/statevariables/statevariable_arithm.go
similarity index 100%
rename from upnp/statevariables/statevariable_arithm.go
rename to upnp/devices/services/statevariables/statevariable_arithm.go
diff --git a/upnp/statevariables/statevariable_cast.go b/upnp/devices/services/statevariables/statevariable_cast.go
similarity index 100%
rename from upnp/statevariables/statevariable_cast.go
rename to upnp/devices/services/statevariables/statevariable_cast.go
diff --git a/upnp/statevariables/statevariable_cmp.go b/upnp/devices/services/statevariables/statevariable_cmp.go
similarity index 100%
rename from upnp/statevariables/statevariable_cmp.go
rename to upnp/devices/services/statevariables/statevariable_cmp.go
diff --git a/upnp/statevariables/statevariable_typechecking.go b/upnp/devices/services/statevariables/statevariable_typechecking.go
similarity index 100%
rename from upnp/statevariables/statevariable_typechecking.go
rename to upnp/devices/services/statevariables/statevariable_typechecking.go
diff --git a/upnp/devices/services/statevariables/statevariableset.go b/upnp/devices/services/statevariables/statevariableset.go
new file mode 100644
index 00000000..79bf8fb6
--- /dev/null
+++ b/upnp/devices/services/statevariables/statevariableset.go
@@ -0,0 +1,32 @@
+package statevariables
+
+import (
+	"iter"
+
+	"gargoton.petite-maison-orange.fr/eric/pmomusic/upnp/objectstore"
+	"github.com/beevik/etree"
+)
+
+type StateVariableSet objectstore.ObjectSet[*StateVariable]
+
+func (m *StateVariableSet) Insert(obj *StateVariable) {
+	(*objectstore.ObjectSet[*StateVariable])(m).Insert(obj)
+}
+
+func (set *StateVariableSet) Contains(obj *StateVariable) bool {
+	return (*objectstore.ObjectSet[*StateVariable])(set).Contains(obj)
+}
+
+func (m *StateVariableSet) All() iter.Seq[*StateVariable] {
+	return (*objectstore.ObjectSet[*StateVariable])(m).All()
+}
+
+func (m *StateVariableSet) ToXMLElement() *etree.Element {
+	elem := etree.NewElement("serviceStateTable")
+
+	for sv := range m.All() {
+		elem.AddChild(sv.ToXMLElement())
+	}
+
+	return elem
+}
diff --git a/upnp/statevariables/statevartype.go b/upnp/devices/services/statevariables/statevartype.go
similarity index 100%
rename from upnp/statevariables/statevartype.go
rename to upnp/devices/services/statevariables/statevartype.go
diff --git a/upnp/statevariables/statevartype_arithm.go b/upnp/devices/services/statevariables/statevartype_arithm.go
similarity index 100%
rename from upnp/statevariables/statevartype_arithm.go
rename to upnp/devices/services/statevariables/statevartype_arithm.go
diff --git a/upnp/statevariables/statevartype_cast.go b/upnp/devices/services/statevariables/statevartype_cast.go
similarity index 100%
rename from upnp/statevariables/statevartype_cast.go
rename to upnp/devices/services/statevariables/statevartype_cast.go
diff --git a/upnp/statevariables/statevartype_cmp.go b/upnp/devices/services/statevariables/statevartype_cmp.go
similarity index 100%
rename from upnp/statevariables/statevartype_cmp.go
rename to upnp/devices/services/statevariables/statevartype_cmp.go
diff --git a/upnp/statevariables/statevartype_typechecking.go b/upnp/devices/services/statevariables/statevartype_typechecking.go
similarity index 100%
rename from upnp/statevariables/statevartype_typechecking.go
rename to upnp/devices/services/statevariables/statevartype_typechecking.go
diff --git a/upnp/statevariables/utils_binary.go b/upnp/devices/services/statevariables/utils_binary.go
similarity index 100%
rename from upnp/statevariables/utils_binary.go
rename to upnp/devices/services/statevariables/utils_binary.go
diff --git a/upnp/statevariables/utils_bool.go b/upnp/devices/services/statevariables/utils_bool.go
similarity index 100%
rename from upnp/statevariables/utils_bool.go
rename to upnp/devices/services/statevariables/utils_bool.go
diff --git a/upnp/statevariables/utils_float.go b/upnp/devices/services/statevariables/utils_float.go
similarity index 100%
rename from upnp/statevariables/utils_float.go
rename to upnp/devices/services/statevariables/utils_float.go
diff --git a/upnp/statevariables/utils_int.go b/upnp/devices/services/statevariables/utils_int.go
similarity index 100%
rename from upnp/statevariables/utils_int.go
rename to upnp/devices/services/statevariables/utils_int.go
diff --git a/upnp/statevariables/utils_numeric_operandes.go b/upnp/devices/services/statevariables/utils_numeric_operandes.go
similarity index 100%
rename from upnp/statevariables/utils_numeric_operandes.go
rename to upnp/devices/services/statevariables/utils_numeric_operandes.go
diff --git a/upnp/statevariables/utils_string.go b/upnp/devices/services/statevariables/utils_string.go
similarity index 100%
rename from upnp/statevariables/utils_string.go
rename to upnp/devices/services/statevariables/utils_string.go
diff --git a/upnp/statevariables/utils_time.go b/upnp/devices/services/statevariables/utils_time.go
similarity index 98%
rename from upnp/statevariables/utils_time.go
rename to upnp/devices/services/statevariables/utils_time.go
index 379dcc73..58405d4f 100644
--- a/upnp/statevariables/utils_time.go
+++ b/upnp/devices/services/statevariables/utils_time.go
@@ -55,7 +55,7 @@ func toTime(v interface{}) (time.Time, error) {
 func parseUPnPTime(t StateVarType, s string) (time.Time, error) {
 	s = strings.TrimSpace(s)
 
-	layouts := []string{}
+	var layouts []string = nil
 
 	switch t {
 	case StateType_Date:
@@ -86,6 +86,7 @@ func parseUPnPTime(t StateVarType, s string) (time.Time, error) {
 			return ts, nil
 		}
 	}
+
 	return time.Time{}, fmt.Errorf("invalid %v value: %q", t, s)
 }
 
diff --git a/upnp/statevariables/utils_uint.go b/upnp/devices/services/statevariables/utils_uint.go
similarity index 100%
rename from upnp/statevariables/utils_uint.go
rename to upnp/devices/services/statevariables/utils_uint.go
diff --git a/upnp/statevariables/utils_uri.go b/upnp/devices/services/statevariables/utils_uri.go
similarity index 100%
rename from upnp/statevariables/utils_uri.go
rename to upnp/devices/services/statevariables/utils_uri.go
diff --git a/upnp/statevariables/utils_uuid.go b/upnp/devices/services/statevariables/utils_uuid.go
similarity index 100%
rename from upnp/statevariables/utils_uuid.go
rename to upnp/devices/services/statevariables/utils_uuid.go
diff --git a/upnp/statevariables/valuerange.go b/upnp/devices/services/statevariables/valuerange.go
similarity index 100%
rename from upnp/statevariables/valuerange.go
rename to upnp/devices/services/statevariables/valuerange.go
diff --git a/upnp/objectstore/object.go b/upnp/objectstore/object.go
new file mode 100644
index 00000000..922067dd
--- /dev/null
+++ b/upnp/objectstore/object.go
@@ -0,0 +1,69 @@
+package objectstore
+
+import (
+	"iter"
+
+	"github.com/google/uuid"
+	log "github.com/sirupsen/logrus"
+)
+
+type ObjectIdSet map[uuid.UUID]struct{}
+
+func (set ObjectIdSet) Contains(id uuid.UUID) bool {
+	_, ok := set[id]
+	return ok
+}
+
+func (set ObjectIdSet) Add(id uuid.UUID) {
+	set[id] = struct{}{}
+}
+
+func (set ObjectIdSet) Remove(id uuid.UUID) {
+	delete(set, id)
+}
+
+func (set ObjectIdSet) Clear() {
+	for k := range set {
+		delete(set, k)
+	}
+}
+
+func (set ObjectIdSet) Len() int {
+	return len(set)
+}
+
+func (set ObjectIdSet) All() iter.Seq[uuid.UUID] {
+	return func(yield func(uuid.UUID) bool) {
+		for uuid := range set {
+			if !yield(uuid) {
+				return
+			}
+		}
+	}
+}
+
+var objectstore = make(map[uuid.UUID]Object)
+
+func RegisterObject(o Object) uuid.UUID {
+	id := uuid.New()
+	objectstore[id] = o
+
+	return id
+}
+
+func GetObject(id uuid.UUID) (Object, bool) {
+	o, ok := objectstore[id]
+	return o, ok
+}
+
+func RemoveObject(id uuid.UUID) {
+	if _, ok := objectstore[id]; !ok {
+		delete(objectstore, id)
+		return
+	}
+	log.Warnf("Object %s not found in objectstore", id)
+}
+
+func CountOfStoredObjects() int {
+	return len(objectstore)
+}
diff --git a/upnp/objectstore/objectset.go b/upnp/objectstore/objectset.go
new file mode 100644
index 00000000..affea4e2
--- /dev/null
+++ b/upnp/objectstore/objectset.go
@@ -0,0 +1,29 @@
+package objectstore
+
+import "iter"
+
+type Object interface {
+	Name() string
+	TypeID() string
+}
+
+type ObjectSet[T Object] map[string]T
+
+func (m *ObjectSet[T]) Insert(obj T) {
+	(*m)[obj.Name()] = obj
+}
+
+func (set *ObjectSet[T]) Contains(obj T) bool {
+	_, ok := (*set)[obj.Name()]
+	return ok
+}
+
+func (m *ObjectSet[T]) All() iter.Seq[T] {
+	return func(yield func(T) bool) {
+		for _, sv := range *m {
+			if !yield(sv) {
+				return
+			}
+		}
+	}
+}