diff --git a/message/interactive.go b/message/interactive.go
index 01c42f3..a36e638 100644
--- a/message/interactive.go
+++ b/message/interactive.go
@@ -15,18 +15,15 @@ func NewInteractiveReplyButtons(to string, opts InteractiveReplyButtonsOpts) Env
 		}
 	}
 
-	return Envelope{
-		MessagingProduct: "whatsapp",
-		RecipientType:    "individual",
-		To:               to,
-		Type:             "interactive",
-		Interactive: &Interactive{
-			Header: opts.Header,
-			Body:   TextObject{Text: opts.Body},
-			Type:   "button",
-			Action: Action{
-				Buttons: &buttons,
-			},
+	e := baseEnvelope(to)
+	e.Type = "interactive"
+	e.Interactive = &Interactive{
+		Header: opts.Header,
+		Body:   TextObject{Text: opts.Body},
+		Type:   "button",
+		Action: Action{
+			Buttons: &buttons,
 		},
 	}
+	return e
 }
diff --git a/message/message.go b/message/message.go
index c368cf3..5600186 100644
--- a/message/message.go
+++ b/message/message.go
@@ -1,9 +1,34 @@
 package message
 
+import "regexp"
+
+// bsuidPattern matches regular BSUIDs (e.g. US.13491208655302741918) and
+// parent BSUIDs (e.g. US.ENT.11815799212886844830):
+// 2-letter ISO country code + "." + optional "ENT." + 1–128 alphanumeric chars.
+var bsuidPattern = regexp.MustCompile(`^[A-Za-z]{2}\.(ENT\.)?[A-Za-z0-9]{1,128}$`)
+
+func isBSUID(s string) bool {
+	return bsuidPattern.MatchString(s)
+}
+
+func baseEnvelope(to string) Envelope {
+	e := Envelope{
+		MessagingProduct: "whatsapp",
+		RecipientType:    "individual",
+	}
+	if isBSUID(to) {
+		e.Recipient = to
+	} else {
+		e.To = to
+	}
+	return e
+}
+
 type Envelope struct {
 	MessagingProduct string           `json:"messaging_product"`
 	RecipientType    string           `json:"recipient_type,omitempty"`
 	To               string           `json:"to,omitempty"`
+	Recipient        string           `json:"recipient,omitempty"`
 	Type             string           `json:"type,omitempty"`
 	Text             *Text            `json:"text,omitempty"`
 	Image            *Image           `json:"image,omitempty"`
@@ -115,57 +140,48 @@ type NewFlowOpts struct {
 }
 
 func NewText(to string, opts NewTextOpts) Envelope {
-	return Envelope{
-		MessagingProduct: "whatsapp",
-		RecipientType:    "individual",
-		To:               to,
-		Type:             "text",
-		Text: &Text{
-			Body:       opts.Text,
-			PreviewURL: opts.PreviewURL,
-		},
+	e := baseEnvelope(to)
+	e.Type = "text"
+	e.Text = &Text{
+		Body:       opts.Text,
+		PreviewURL: opts.PreviewURL,
 	}
+	return e
 }
 
 func NewImageLink(to string, opts NewImageLinkOpts) Envelope {
-	return Envelope{
-		MessagingProduct: "whatsapp",
-		RecipientType:    "individual",
-		To:               to,
-		Type:             "image",
-		Image: &Image{
-			Link:    opts.Link,
-			Caption: opts.Caption,
-		},
+	e := baseEnvelope(to)
+	e.Type = "image"
+	e.Image = &Image{
+		Link:    opts.Link,
+		Caption: opts.Caption,
 	}
+	return e
 }
 
 func NewInteractiveFlow(to string, opts NewFlowOpts) Envelope {
 	flow := "flow"
-	return Envelope{
-		MessagingProduct: "whatsapp",
-		RecipientType:    "individual",
-		To:               to,
-		Type:             "interactive",
-		Interactive: &Interactive{
-			Type:   "flow",
-			Header: opts.Header,
-			Body:   opts.Body,
-			Footer: opts.Footer,
-			Action: Action{
-				Name: &flow,
-				Parameters: &Parameters{
-					Mode:               opts.FlowMode,
-					FlowMessageVersion: "3",
-					FlowToken:          opts.FlowToken,
-					FlowID:             opts.FlowId,
-					FlowCTA:            opts.FlowCTA,
-					FlowAction:         "navigate",
-					FlowActionPayload:  FlowAction{Screen: opts.FirstScreen},
-				},
+	e := baseEnvelope(to)
+	e.Type = "interactive"
+	e.Interactive = &Interactive{
+		Type:   "flow",
+		Header: opts.Header,
+		Body:   opts.Body,
+		Footer: opts.Footer,
+		Action: Action{
+			Name: &flow,
+			Parameters: &Parameters{
+				Mode:               opts.FlowMode,
+				FlowMessageVersion: "3",
+				FlowToken:          opts.FlowToken,
+				FlowID:             opts.FlowId,
+				FlowCTA:            opts.FlowCTA,
+				FlowAction:         "navigate",
+				FlowActionPayload:  FlowAction{Screen: opts.FirstScreen},
 			},
 		},
 	}
+	return e
 }
 
 func NewMessageRead(messageId string, typingIndicator bool) Envelope {
@@ -185,27 +201,19 @@ func NewMessageRead(messageId string, typingIndicator bool) Envelope {
 }
 
 func NewDocument(to string, opts NewDocumentOpts) Envelope {
-	return Envelope{
-		MessagingProduct: "whatsapp",
-		RecipientType:    "individual",
-		To:               to,
-		Type:             "document",
-		Document: &Document{
-			Link:     opts.Link,
-			Caption:  opts.Caption,
-			Filename: opts.Filename,
-		},
+	e := baseEnvelope(to)
+	e.Type = "document"
+	e.Document = &Document{
+		Link:     opts.Link,
+		Caption:  opts.Caption,
+		Filename: opts.Filename,
 	}
+	return e
 }
 
 func NewSticker(to, link string) Envelope {
-	return Envelope{
-		MessagingProduct: "whatsapp",
-		RecipientType:    "individual",
-		To:               to,
-		Type:             "sticker",
-		Sticker: &Sticker{
-			Link: link,
-		},
-	}
+	e := baseEnvelope(to)
+	e.Type = "sticker"
+	e.Sticker = &Sticker{Link: link}
+	return e
 }
diff --git a/message/message_test.go b/message/message_test.go
index 5c2584a..ae8cfd0 100644
--- a/message/message_test.go
+++ b/message/message_test.go
@@ -14,6 +14,31 @@ var expectedMessageReadWithTypingJSON string
 //go:embed testdata/message_read_without_typing.json
 var expectedMessageReadWithoutTypingJSON string
 
+func TestBaseEnvelopeRouting(t *testing.T) {
+	tests := []struct {
+		name          string
+		to            string
+		wantTo        string
+		wantRecipient string
+	}{
+		{name: "phoneNumber", to: "16505551234", wantTo: "16505551234", wantRecipient: ""},
+		{name: "bsuid", to: "US.123", wantTo: "", wantRecipient: "US.123"},
+		{name: "parentBsuid", to: "US.ENT.123", wantTo: "", wantRecipient: "US.ENT.123"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := baseEnvelope(tt.to)
+			if e.To != tt.wantTo {
+				t.Errorf("To: got %q, want %q", e.To, tt.wantTo)
+			}
+			if e.Recipient != tt.wantRecipient {
+				t.Errorf("Recipient: got %q, want %q", e.Recipient, tt.wantRecipient)
+			}
+		})
+	}
+}
+
 func TestNewMessageRead(t *testing.T) {
 	tests := []struct {
 		messageID       string
diff --git a/webhook/webhook.go b/webhook/webhook.go
index 98c64d6..88e0def 100644
--- a/webhook/webhook.go
+++ b/webhook/webhook.go
@@ -28,22 +28,27 @@ type Metadata struct {
 }
 
 type Contact struct {
-	WhatsappID string  `json:"wa_id"`
-	Profile    Profile `json:"profile"`
+	WhatsappID   string  `json:"wa_id"`
+	UserID       string  `json:"user_id"`
+	ParentUserID string  `json:"parent_user_id"`
+	Profile      Profile `json:"profile"`
 }
 
 type Profile struct {
-	Name string `json:"name"`
+	Name     string `json:"name"`
+	Username string `json:"username"`
 }
 
 type Message struct {
-	From        string      `json:"from"`
-	ID          string      `json:"id"`
-	Timestamp   string      `json:"timestamp"`
-	Type        string      `json:"type"`
-	Context     *Context    `json:"context"`
-	Text        Text        `json:"text"`
-	Interactive Interactive `json:"interactive"`
+	From             string      `json:"from"`
+	FromUserID       string      `json:"from_user_id"`
+	FromParentUserID string      `json:"from_parent_user_id"`
+	ID               string      `json:"id"`
+	Timestamp        string      `json:"timestamp"`
+	Type             string      `json:"type"`
+	Context          *Context    `json:"context"`
+	Text             Text        `json:"text"`
+	Interactive      Interactive `json:"interactive"`
 }
 
 type Text struct {