diff --git a/internal/domain/email_provider_postmark.go b/internal/domain/email_provider_postmark.go
index 321663c0..dafbbbb9 100644
--- a/internal/domain/email_provider_postmark.go
+++ b/internal/domain/email_provider_postmark.go
@@ -2,6 +2,7 @@ package domain
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 
 	"github.com/Notifuse/notifuse/pkg/crypto"
@@ -9,13 +10,15 @@ import (
 
 // PostmarkWebhookPayload represents the base webhook payload from Postmark
 type PostmarkWebhookPayload struct {
-	RecordType    string            `json:"RecordType"`
-	MessageStream string            `json:"MessageStream"`
-	ID            string            `json:"ID"`
-	MessageID     string            `json:"MessageID"`
-	ServerID      int               `json:"ServerID"`
-	Metadata      map[string]string `json:"Metadata,omitempty"`
-	Tag           string            `json:"Tag,omitempty"`
+	RecordType    string `json:"RecordType"`
+	MessageStream string `json:"MessageStream"`
+	// ID is a number in Postmark Bounce/SpamComplaint payloads (e.g. 692560173);
+	// json.Number accepts both numeric and string-encoded values.
+	ID        json.Number       `json:"ID"`
+	MessageID string            `json:"MessageID"`
+	ServerID  int               `json:"ServerID"`
+	Metadata  map[string]string `json:"Metadata,omitempty"`
+	Tag       string            `json:"Tag,omitempty"`
 
 	// Delivered event specific fields
 	DeliveredFields *PostmarkDeliveredFields `json:"-"`
diff --git a/internal/service/inbound_webhook_event_service.go b/internal/service/inbound_webhook_event_service.go
index 070a4117..72089401 100644
--- a/internal/service/inbound_webhook_event_service.go
+++ b/internal/service/inbound_webhook_event_service.go
@@ -766,7 +766,12 @@ func (s *InboundWebhookEventService) processPostmarkWebhook(integrationID string
 			complaintFeedbackType = typeStr
 		}
 
-		if t, ok := jsonData["ComplainedAt"].(string); ok && t != "" {
+		// Postmark sends the complaint time in "BouncedAt"; keep "ComplainedAt" for compatibility.
+		complainedAt, _ := jsonData["ComplainedAt"].(string)
+		if complainedAt == "" {
+			complainedAt, _ = jsonData["BouncedAt"].(string)
+		}
+		if t := complainedAt; t != "" {
 			if parsedTime, err := time.Parse(time.RFC3339, t); err == nil {
 				timestamp = parsedTime
 			} else {
diff --git a/internal/service/inbound_webhook_event_service_test.go b/internal/service/inbound_webhook_event_service_test.go
index 9e459571..d927585c 100644
--- a/internal/service/inbound_webhook_event_service_test.go
+++ b/internal/service/inbound_webhook_event_service_test.go
@@ -785,6 +785,31 @@ func TestProcessPostmarkWebhook(t *testing.T) {
 		assert.Equal(t, "message1", *events[0].MessageID)
 	})
 
+	// Postmark sends "ID" as a JSON number in Bounce/SpamComplaint payloads
+	// (https://postmarkapp.com/developer/webhooks/bounce-webhook). Postmark's webhook
+	// verification sends these payloads and rejects the webhook on any non-2xx.
+	t.Run("Bounce Event with numeric ID (official Postmark payload)", func(t *testing.T) {
+		rawPayload := []byte(`{"RecordType":"Bounce","MessageStream":"broadcast","ID":692560173,"Type":"HardBounce","TypeCode":1,"Name":"Hard bounce","MessageID":"883953f4-6105-42a2-a16a-77a8eac79483","ServerID":23,"Email":"test@example.com","BouncedAt":"2026-11-05T16:33:54.9070259Z","DumpAvailable":true,"Inactive":true,"CanActivate":true,"Subject":"Hello"}`)
+
+		events, err := service.processPostmarkWebhook(integrationID, rawPayload)
+
+		require.NoError(t, err)
+		require.Len(t, events, 1)
+		assert.Equal(t, domain.EmailEventBounce, events[0].Type)
+		assert.Equal(t, "test@example.com", events[0].RecipientEmail)
+	})
+
+	t.Run("SpamComplaint with numeric ID uses BouncedAt as timestamp", func(t *testing.T) {
+		rawPayload := []byte(`{"RecordType":"SpamComplaint","MessageStream":"broadcast","ID":692560174,"Type":"SpamComplaint","TypeCode":100001,"Name":"Spam complaint","MessageID":"883953f4-6105-42a2-a16a-77a8eac79483","ServerID":23,"Email":"test@example.com","BouncedAt":"2026-11-05T16:33:54Z","Subject":"Hello"}`)
+
+		events, err := service.processPostmarkWebhook(integrationID, rawPayload)
+
+		require.NoError(t, err)
+		require.Len(t, events, 1)
+		assert.Equal(t, domain.EmailEventComplaint, events[0].Type)
+		assert.Equal(t, time.Date(2026, 11, 5, 16, 33, 54, 0, time.UTC), events[0].Timestamp.UTC())
+	})
+
 	t.Run("Bounce Event", func(t *testing.T) {
 		// Create test bounce payload using a map to ensure correct JSON structure
 		rawPayload, err := json.Marshal(map[string]interface{}{