diff --git a/store/activity.go b/store/activity.go
index e6c630d7..20da01cc 100644
--- a/store/activity.go
+++ b/store/activity.go
@@ -2,8 +2,30 @@ package store
 
 import (
 	"context"
+
+	storepb "github.com/usememos/memos/proto/gen/store"
 )
 
+type ActivityType string
+
+const (
+	ActivityTypeMemoComment ActivityType = "MEMO_COMMENT"
+)
+
+func (t ActivityType) String() string {
+	return string(t)
+}
+
+type ActivityLevel string
+
+const (
+	ActivityLevelInfo ActivityLevel = "INFO"
+)
+
+func (l ActivityLevel) String() string {
+	return string(l)
+}
+
 type Activity struct {
 	ID int32
 
@@ -12,9 +34,9 @@ type Activity struct {
 	CreatedTs int64
 
 	// Domain specific fields
-	Type    string
-	Level   string
-	Payload string
+	Type    ActivityType
+	Level   ActivityLevel
+	Payload *storepb.ActivityPayload
 }
 
 type FindActivity struct {
diff --git a/store/db/mysql/activity.go b/store/db/mysql/activity.go
index b985a622..075aed0f 100644
--- a/store/db/mysql/activity.go
+++ b/store/db/mysql/activity.go
@@ -5,14 +5,24 @@ import (
 	"strings"
 
 	"github.com/pkg/errors"
+	"google.golang.org/protobuf/encoding/protojson"
 
+	storepb "github.com/usememos/memos/proto/gen/store"
 	"github.com/usememos/memos/store"
 )
 
 func (d *DB) CreateActivity(ctx context.Context, create *store.Activity) (*store.Activity, error) {
+	payloadString := "{}"
+	if create.Payload != nil {
+		bytes, err := protojson.Marshal(create.Payload)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to marshal activity payload")
+		}
+		payloadString = string(bytes)
+	}
 	fields := []string{"`creator_id`", "`type`", "`level`", "`payload`"}
 	placeholder := []string{"?", "?", "?", "?"}
-	args := []any{create.CreatorID, create.Type, create.Level, create.Payload}
+	args := []any{create.CreatorID, create.Type.String(), create.Level.String(), payloadString}
 
 	if create.ID != 0 {
 		fields = append(fields, "`id`")
@@ -64,17 +74,23 @@ func (d *DB) ListActivities(ctx context.Context, find *store.FindActivity) ([]*s
 	list := []*store.Activity{}
 	for rows.Next() {
 		activity := &store.Activity{}
+		var payloadBytes []byte
 		if err := rows.Scan(
 			&activity.ID,
 			&activity.CreatorID,
 			&activity.Type,
 			&activity.Level,
-			&activity.Payload,
+			&payloadBytes,
 			&activity.CreatedTs,
 		); err != nil {
 			return nil, err
 		}
 
+		payload := &storepb.ActivityPayload{}
+		if err := protojsonUnmarshaler.Unmarshal(payloadBytes, payload); err != nil {
+			return nil, err
+		}
+		activity.Payload = payload
 		list = append(list, activity)
 	}
 
diff --git a/store/db/mysql/common.go b/store/db/mysql/common.go
new file mode 100644
index 00000000..37ffe296
--- /dev/null
+++ b/store/db/mysql/common.go
@@ -0,0 +1,9 @@
+package mysql
+
+import "google.golang.org/protobuf/encoding/protojson"
+
+var (
+	protojsonUnmarshaler = protojson.UnmarshalOptions{
+		DiscardUnknown: true,
+	}
+)
diff --git a/store/db/sqlite/activity.go b/store/db/sqlite/activity.go
index 59d9897a..1853df1e 100644
--- a/store/db/sqlite/activity.go
+++ b/store/db/sqlite/activity.go
@@ -4,13 +4,26 @@ import (
 	"context"
 	"strings"
 
+	"github.com/pkg/errors"
+	"google.golang.org/protobuf/encoding/protojson"
+
+	storepb "github.com/usememos/memos/proto/gen/store"
 	"github.com/usememos/memos/store"
 )
 
 func (d *DB) CreateActivity(ctx context.Context, create *store.Activity) (*store.Activity, error) {
+	payloadString := "{}"
+	if create.Payload != nil {
+		bytes, err := protojson.Marshal(create.Payload)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to marshal activity payload")
+		}
+		payloadString = string(bytes)
+	}
+
 	fields := []string{"`creator_id`", "`type`", "`level`", "`payload`"}
 	placeholder := []string{"?", "?", "?", "?"}
-	args := []any{create.CreatorID, create.Type, create.Level, create.Payload}
+	args := []any{create.CreatorID, create.Type.String(), create.Level.String(), payloadString}
 
 	if create.ID != 0 {
 		fields = append(fields, "`id`")
@@ -52,17 +65,23 @@ func (d *DB) ListActivities(ctx context.Context, find *store.FindActivity) ([]*s
 	list := []*store.Activity{}
 	for rows.Next() {
 		activity := &store.Activity{}
+		var payloadBytes []byte
 		if err := rows.Scan(
 			&activity.ID,
 			&activity.CreatorID,
 			&activity.Type,
 			&activity.Level,
-			&activity.Payload,
+			&payloadBytes,
 			&activity.CreatedTs,
 		); err != nil {
 			return nil, err
 		}
 
+		payload := &storepb.ActivityPayload{}
+		if err := protojsonUnmarshaler.Unmarshal(payloadBytes, payload); err != nil {
+			return nil, err
+		}
+		activity.Payload = payload
 		list = append(list, activity)
 	}
 
diff --git a/test/store/activity_test.go b/test/store/activity_test.go
new file mode 100644
index 00000000..d5b996d2
--- /dev/null
+++ b/test/store/activity_test.go
@@ -0,0 +1,33 @@
+package teststore
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	storepb "github.com/usememos/memos/proto/gen/store"
+	"github.com/usememos/memos/store"
+)
+
+func TestActivityStore(t *testing.T) {
+	ctx := context.Background()
+	ts := NewTestingStore(ctx, t)
+	user, err := createTestingHostUser(ctx, ts)
+	require.NoError(t, err)
+	create := &store.Activity{
+		CreatorID: user.ID,
+		Type:      store.ActivityTypeMemoComment,
+		Level:     store.ActivityLevelInfo,
+		Payload:   &storepb.ActivityPayload{},
+	}
+	activity, err := ts.CreateActivity(ctx, create)
+	require.NoError(t, err)
+	require.NotNil(t, activity)
+	activities, err := ts.ListActivities(ctx, &store.FindActivity{
+		ID: &activity.ID,
+	})
+	require.NoError(t, err)
+	require.Equal(t, 1, len(activities))
+	require.Equal(t, activity, activities[0])
+}