diff --git a/observability_types.go b/observability_types.go
index 7541bc3..fbe0ed0 100644
--- a/observability_types.go
+++ b/observability_types.go
@@ -1,7 +1,5 @@
 package proton
 
-import "time"
-
 type ObservabilityBatch struct {
 	Metrics []ObservabilityMetric `json:"Metrics"`
 }
@@ -9,6 +7,6 @@ type ObservabilityBatch struct {
 type ObservabilityMetric struct {
 	Name      string      `json:"Name"`
 	Version   int         `json:"Version"`
-	Timestamp time.Time   `json:"Timestamp"`
+	Timestamp int64       `json:"Timestamp"` // Unix timestamp
 	Data      interface{} `json:"Data"`
 }