diff --git a/api.go b/api.go
index 4a6285bc..8058bda6 100644
--- a/api.go
+++ b/api.go
@@ -81,14 +81,13 @@ func (api *API) addAlerts(w http.ResponseWriter, r *http.Request) {
 	for _, alert := range alerts {
 		now := time.Now()
 
-		if alert.Timestamp.IsZero() {
-			alert.Timestamp = now
+		alert.UpdatedAt = now
+
+		if alert.StartsAt.IsZero() {
+			alert.StartsAt = now
 		}
-		if alert.CreatedAt.IsZero() {
-			alert.CreatedAt = now
-		}
-		if alert.ResolvedAt.IsZero() {
-			alert.ResolvedAt = alert.CreatedAt.Add(ResolveTimeout)
+		if alert.EndsAt.IsZero() {
+			alert.EndsAt = alert.StartsAt.Add(ResolveTimeout)
 		}
 	}
 
diff --git a/dispatch.go b/dispatch.go
index 3d05c2cb..0fdeea7b 100644
--- a/dispatch.go
+++ b/dispatch.go
@@ -238,7 +238,7 @@ func (ag *aggrGroup) insert(alert *types.Alert) {
 
 	// Immediately trigger a flush if the wait duration for this
 	// alert is already over.
-	if !ag.hasSent && alert.Timestamp.Add(ag.opts.GroupWait).Before(time.Now()) {
+	if !ag.hasSent && alert.UpdatedAt.Add(ag.opts.GroupWait).Before(time.Now()) {
 		ag.next.Reset(0)
 	}
 }
diff --git a/notify/notify_test.go b/notify/notify_test.go
index b2fd9214..12c196df 100644
--- a/notify/notify_test.go
+++ b/notify/notify_test.go
@@ -52,16 +52,16 @@ func TestDedupingNotifier(t *testing.T) {
 			Labels: model.LabelSet{"alertname": "2"},
 		},
 		{
-			Labels:     model.LabelSet{"alertname": "3"},
-			ResolvedAt: now.Add(-20 * time.Minute),
+			Labels: model.LabelSet{"alertname": "3"},
+			EndsAt: now.Add(-20 * time.Minute),
 		},
 		{
-			Labels:     model.LabelSet{"alertname": "4"},
-			ResolvedAt: now.Add(-10 * time.Minute),
+			Labels: model.LabelSet{"alertname": "4"},
+			EndsAt: now.Add(-10 * time.Minute),
 		},
 		{
-			Labels:     model.LabelSet{"alertname": "5"},
-			ResolvedAt: now.Add(-10 * time.Minute),
+			Labels: model.LabelSet{"alertname": "5"},
+			EndsAt: now.Add(-10 * time.Minute),
 		},
 		{
 			Labels: model.LabelSet{"alertname": "6"},
diff --git a/types/types.go b/types/types.go
index f24ac7e6..ae7ba5bb 100644
--- a/types/types.go
+++ b/types/types.go
@@ -34,11 +34,11 @@ type Alert struct {
 	// Extra key/value information which does not define alert identity.
 	Annotations Annotations `json:"annotations,omitempty"`
 
-	CreatedAt  time.Time `json:"createdAt,omitempty"`
-	ResolvedAt time.Time `json:"resolvedAt,omitempty"`
+	StartsAt time.Time `json:"startsAt,omitempty"`
+	EndsAt   time.Time `json:"endsAt,omitempty"`
 
 	// The authoritative timestamp.
-	Timestamp time.Time `json:"timestamp"`
+	UpdatedAt time.Time `json:"timestamp"`
 }
 
 // Name returns the name of the alert. It is equivalent to the "alertname" label.
@@ -78,17 +78,17 @@ func (a *Alert) String() string {
 }
 
 func (a *Alert) Resolved() bool {
-	if a.ResolvedAt.IsZero() {
+	if a.EndsAt.IsZero() {
 		return false
 	}
-	return !a.ResolvedAt.After(time.Now())
+	return !a.EndsAt.After(time.Now())
 }
 
 // alertTimeline is a list of alerts sorted by their timestamp.
 type alertTimeline []*Alert
 
 func (at alertTimeline) Len() int           { return len(at) }
-func (at alertTimeline) Less(i, j int) bool { return at[i].Timestamp.Before(at[j].Timestamp) }
+func (at alertTimeline) Less(i, j int) bool { return at[i].UpdatedAt.Before(at[j].UpdatedAt) }
 func (at alertTimeline) Swap(i, j int)      { at[i], at[j] = at[j], at[i] }
 
 // A Silencer determines whether a given label set is muted.