diff --git a/api/client_test.go b/api/client_test.go
index e989314..7ae5c4c 100644
--- a/api/client_test.go
+++ b/api/client_test.go
@@ -49,7 +49,7 @@ func TestClient_ReadUsage(t *testing.T) {
 		},
 		"fail": {
 			svcPermits: permits.NewServiceMock(),
-			subj:       usage.SubjectPublishMessages,
+			subj:       usage.SubjectPublishEvents,
 			userId:     "fail",
 			err:        permits.ErrInternal,
 		},
@@ -92,7 +92,7 @@ func TestClient_ReadUsageLimit(t *testing.T) {
 		},
 		"both group and user missing": {
 			svcLimits: limits.NewServiceMock(),
-			subj:      usage.SubjectPublishMessages,
+			subj:      usage.SubjectPublishEvents,
 			userId:    "group_missing",
 		},
 		"group present, user missing": {
@@ -116,7 +116,7 @@ func TestClient_ReadUsageLimit(t *testing.T) {
 		},
 		"fail": {
 			svcLimits: limits.NewServiceMock(),
-			subj:      usage.SubjectPublishMessages,
+			subj:      usage.SubjectPublishEvents,
 			userId:    "fail",
 			err:       limits.ErrInternal,
 		},
diff --git a/api/grpc/limits/service_test.go b/api/grpc/limits/service_test.go
index e903fa7..780a192 100644
--- a/api/grpc/limits/service_test.go
+++ b/api/grpc/limits/service_test.go
@@ -19,7 +19,7 @@ func TestService_Get(t *testing.T) {
 	}{
 		"ok": {
 			userId:  "user0",
-			subject: usage.SubjectPublishMessages,
+			subject: usage.SubjectPublishEvents,
 			lim: usage.Limit{
 				Count:  1,
 				UserId: "user0",
@@ -37,7 +37,7 @@ func TestService_Get(t *testing.T) {
 		},
 		"fail auth": {
 			userId:  "fail_auth",
-			subject: usage.SubjectPublishMessages,
+			subject: usage.SubjectPublishEvents,
 			err:     auth.ErrAuth,
 		},
 	}
diff --git a/api/grpc/permits/service_test.go b/api/grpc/permits/service_test.go
index ad16b8e..87d2043 100644
--- a/api/grpc/permits/service_test.go
+++ b/api/grpc/permits/service_test.go
@@ -20,7 +20,7 @@ func TestService_GetUsage(t *testing.T) {
 	}{
 		"ok": {
 			userId:  "user0",
-			subject: usage.SubjectPublishMessages,
+			subject: usage.SubjectPublishEvents,
 			out: usage.Usage{
 				Count:      1,
 				CountTotal: 2,
@@ -39,7 +39,7 @@ func TestService_GetUsage(t *testing.T) {
 		},
 		"fail auth": {
 			userId:  "fail_auth",
-			subject: usage.SubjectPublishMessages,
+			subject: usage.SubjectPublishEvents,
 			err:     auth.ErrAuth,
 		},
 	}
diff --git a/api/grpc/subject/encode.go b/api/grpc/subject/encode.go
index 2525fae..c9547fd 100644
--- a/api/grpc/subject/encode.go
+++ b/api/grpc/subject/encode.go
@@ -10,10 +10,10 @@ var ErrInvalidSubject = errors.New("unrecognized subject")
 
 func Encode(src usage.Subject) (dst Subject, err error) {
 	switch src {
-	case usage.SubjectPublishMessages:
-		dst = Subject_PublishMessages
 	case usage.SubjectSubscriptions:
 		dst = Subject_Subscriptions
+	case usage.SubjectPublishEvents:
+		dst = Subject_PublishEvents
 	default:
 		err = fmt.Errorf("%w: %s", ErrInvalidSubject, src)
 	}
diff --git a/api/grpc/subject/subject.pb.go b/api/grpc/subject/subject.pb.go
index ed564e4..4ed983d 100644
--- a/api/grpc/subject/subject.pb.go
+++ b/api/grpc/subject/subject.pb.go
@@ -23,22 +23,22 @@ const (
 type Subject int32
 
 const (
-	Subject_Undefined       Subject = 0
-	Subject_PublishMessages Subject = 1
-	Subject_Subscriptions   Subject = 2
+	Subject_Undefined     Subject = 0
+	Subject_Subscriptions Subject = 1
+	Subject_PublishEvents Subject = 2
 )
 
 // Enum value maps for Subject.
 var (
 	Subject_name = map[int32]string{
 		0: "Undefined",
-		1: "PublishMessages",
-		2: "Subscriptions",
+		1: "Subscriptions",
+		2: "PublishEvents",
 	}
 	Subject_value = map[string]int32{
-		"Undefined":       0,
-		"PublishMessages": 1,
-		"Subscriptions":   2,
+		"Undefined":     0,
+		"Subscriptions": 1,
+		"PublishEvents": 2,
 	}
 )
 
@@ -75,15 +75,15 @@ var file_api_grpc_subject_subject_proto_rawDesc = []byte{
 	0x0a, 0x1e, 0x61, 0x70, 0x69, 0x2f, 0x67, 0x72, 0x70, 0x63, 0x2f, 0x73, 0x75, 0x62, 0x6a, 0x65,
 	0x63, 0x74, 0x2f, 0x73, 0x75, 0x62, 0x6a, 0x65, 0x63, 0x74, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f,
 	0x12, 0x13, 0x61, 0x77, 0x61, 0x6b, 0x61, 0x72, 0x69, 0x2e, 0x61, 0x70, 0x69, 0x2e, 0x73, 0x75,
-	0x62, 0x6a, 0x65, 0x63, 0x74, 0x2a, 0x40, 0x0a, 0x07, 0x53, 0x75, 0x62, 0x6a, 0x65, 0x63, 0x74,
+	0x62, 0x6a, 0x65, 0x63, 0x74, 0x2a, 0x3e, 0x0a, 0x07, 0x53, 0x75, 0x62, 0x6a, 0x65, 0x63, 0x74,
 	0x12, 0x0d, 0x0a, 0x09, 0x55, 0x6e, 0x64, 0x65, 0x66, 0x69, 0x6e, 0x65, 0x64, 0x10, 0x00, 0x12,
-	0x13, 0x0a, 0x0f, 0x50, 0x75, 0x62, 0x6c, 0x69, 0x73, 0x68, 0x4d, 0x65, 0x73, 0x73, 0x61, 0x67,
-	0x65, 0x73, 0x10, 0x01, 0x12, 0x11, 0x0a, 0x0d, 0x53, 0x75, 0x62, 0x73, 0x63, 0x72, 0x69, 0x70,
-	0x74, 0x69, 0x6f, 0x6e, 0x73, 0x10, 0x02, 0x42, 0x33, 0x5a, 0x31, 0x67, 0x69, 0x74, 0x68, 0x75,
-	0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x61, 0x77, 0x61, 0x6b, 0x61, 0x72, 0x69, 0x2f, 0x63, 0x6c,
-	0x69, 0x65, 0x6e, 0x74, 0x2d, 0x73, 0x64, 0x6b, 0x2d, 0x67, 0x6f, 0x2f, 0x61, 0x70, 0x69, 0x2f,
-	0x67, 0x72, 0x70, 0x63, 0x2f, 0x73, 0x75, 0x62, 0x6a, 0x65, 0x63, 0x74, 0x62, 0x06, 0x70, 0x72,
-	0x6f, 0x74, 0x6f, 0x33,
+	0x11, 0x0a, 0x0d, 0x53, 0x75, 0x62, 0x73, 0x63, 0x72, 0x69, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73,
+	0x10, 0x01, 0x12, 0x11, 0x0a, 0x0d, 0x50, 0x75, 0x62, 0x6c, 0x69, 0x73, 0x68, 0x45, 0x76, 0x65,
+	0x6e, 0x74, 0x73, 0x10, 0x02, 0x42, 0x33, 0x5a, 0x31, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e,
+	0x63, 0x6f, 0x6d, 0x2f, 0x61, 0x77, 0x61, 0x6b, 0x61, 0x72, 0x69, 0x2f, 0x63, 0x6c, 0x69, 0x65,
+	0x6e, 0x74, 0x2d, 0x73, 0x64, 0x6b, 0x2d, 0x67, 0x6f, 0x2f, 0x61, 0x70, 0x69, 0x2f, 0x67, 0x72,
+	0x70, 0x63, 0x2f, 0x73, 0x75, 0x62, 0x6a, 0x65, 0x63, 0x74, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74,
+	0x6f, 0x33,
 }
 
 var (
diff --git a/api/grpc/subject/subject.proto b/api/grpc/subject/subject.proto
index 6b907e1..78cf9d7 100644
--- a/api/grpc/subject/subject.proto
+++ b/api/grpc/subject/subject.proto
@@ -6,6 +6,6 @@ option go_package = "github.com/awakari/client-sdk-go/api/grpc/subject";
 
 enum Subject {
   Undefined = 0;
-  PublishMessages = 1;
-  Subscriptions = 2;
-}
\ No newline at end of file
+  Subscriptions = 1;
+  PublishEvents = 2;
+}
diff --git a/int_test.go b/int_test.go
index c202178..4e1c2dd 100644
--- a/int_test.go
+++ b/int_test.go
@@ -91,7 +91,7 @@ func TestPublicApiUsage(t *testing.T) {
 
 	// Get the initial Publish Messages API Usage
 	var usagePubMsgsStart usage.Usage
-	usagePubMsgsStart, err = client.ReadUsage(ctx, userId, usage.SubjectPublishMessages)
+	usagePubMsgsStart, err = client.ReadUsage(ctx, userId, usage.SubjectPublishEvents)
 	assert.Nil(t, err)
 
 	// Write a Message
@@ -132,7 +132,7 @@ func TestPublicApiUsage(t *testing.T) {
 
 	// Check the Publish Messages API Usage change
 	var usagePubMsgs usage.Usage
-	usagePubMsgs, err = client.ReadUsage(ctx, userId, usage.SubjectPublishMessages)
+	usagePubMsgs, err = client.ReadUsage(ctx, userId, usage.SubjectPublishEvents)
 	assert.Nil(t, err)
 	assert.Equal(t, usagePubMsgsStart.Count+1, usagePubMsgs.Count)
 	assert.Equal(t, usagePubMsgsStart.CountTotal+1, usagePubMsgs.CountTotal)
diff --git a/model/usage/subject.go b/model/usage/subject.go
index 77032c7..64c8206 100644
--- a/model/usage/subject.go
+++ b/model/usage/subject.go
@@ -4,14 +4,14 @@ type Subject int
 
 const (
 	SubjectUndefined Subject = iota
-	SubjectPublishMessages
 	SubjectSubscriptions
+	SubjectPublishEvents
 )
 
 func (s Subject) String() string {
 	return [...]string{
 		"SubjectUndefined",
-		"SubjectPublishMessages",
 		"SubjectSubscriptions",
+		"SubjectPublishEvents",
 	}[s]
 }