diff --git a/service/apinode/aggregator/aggregator.go b/service/apinode/aggregator/aggregator.go
index 54ff3372..2ab44633 100644
--- a/service/apinode/aggregator/aggregator.go
+++ b/service/apinode/aggregator/aggregator.go
@@ -35,7 +35,7 @@ func Run(projectManager *project.Manager, db *apidb.DB, sequencerAddr string, in
 			taskMap[k] = append(taskMap[k], ts[i])
 		}
 
-		for _, tasks := range taskMap {
+		for taskMapKey, tasks := range taskMap {
 			pid, ok := new(big.Int).SetString(tasks[0].ProjectID, 10)
 			if !ok {
 				slog.Error("failed to decode project id string", "project_string", tasks[0].ProjectID)
@@ -53,8 +53,19 @@ func Run(projectManager *project.Manager, db *apidb.DB, sequencerAddr string, in
 				continue
 			}
 			if cfg.ProofType == "movement" {
-				prevTaskID := tasks[0].TaskID
-				tasks[len(tasks)-1].PrevTaskID = prevTaskID
+				now := time.Now()
+				hoursAgo24 := now.Add(-24 * time.Hour) // TODO move to project config
+				count, err := db.CountSettledTask(tasks[0].ProjectID, tasks[0].DevicePubKey, hoursAgo24, now)
+				if err != nil {
+					slog.Error("failed to count settled task", "error", err, "project_id", pid.String())
+					continue
+				}
+				if count >= 5 { // TODO move to project config
+					delete(taskMap, taskMapKey)
+				} else {
+					prevTaskID := tasks[0].TaskID
+					tasks[len(tasks)-1].PrevTaskID = prevTaskID
+				}
 			}
 		}
 
diff --git a/service/apinode/db/sqlite.go b/service/apinode/db/sqlite.go
index 48f5486e..678a3d89 100644
--- a/service/apinode/db/sqlite.go
+++ b/service/apinode/db/sqlite.go
@@ -2,6 +2,7 @@ package db
 
 import (
 	"math/big"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/pkg/errors"
@@ -24,8 +25,10 @@ type AssignedTask struct {
 
 type SettledTask struct {
 	gorm.Model
-	TaskID string `gorm:"uniqueIndex:settled_task_uniq,not null"`
-	Tx     string `gorm:"not null"`
+	TaskID       string `gorm:"uniqueIndex:settled_task_uniq,not null"`
+	ProjectID    string `gorm:"index:settled_task_query,not null"`
+	DevicePubKey string `gorm:"index:settled_task_query,not null"`
+	Tx           string `gorm:"not null"`
 }
 
 type ProjectDevice struct {
@@ -89,11 +92,17 @@ func (p *DB) UpsertAssignedTask(taskID common.Hash, prover common.Address) error
 }
 
 func (p *DB) UpsertSettledTask(taskID, tx common.Hash) error {
+	chTask, err := p.FetchTask(taskID)
+	if err != nil {
+		return err
+	}
 	t := SettledTask{
-		TaskID: taskID.Hex(),
-		Tx:     tx.Hex(),
+		TaskID:       taskID.Hex(),
+		ProjectID:    chTask.ProjectID,
+		DevicePubKey: chTask.DevicePubKey,
+		Tx:           tx.Hex(),
 	}
-	err := p.sqlite.Clauses(clause.OnConflict{
+	err = p.sqlite.Clauses(clause.OnConflict{
 		Columns:   []clause.Column{{Name: "task_id"}},
 		DoUpdates: clause.AssignmentColumns([]string{"tx"}),
 	}).Create(&t).Error
@@ -122,6 +131,18 @@ func (p *DB) FetchSettledTask(taskID common.Hash) (*SettledTask, error) {
 	return &t, nil
 }
 
+func (p *DB) CountSettledTask(projectID, devicePubKey string, begin, end time.Time) (int64, error) {
+	var c int64
+	if err := p.sqlite.Where("project_id = ?", projectID).
+		Where("device_pub_key = ?", devicePubKey).
+		Where("created_at > ?", begin).
+		Where("created_at <= ?", end).
+		Model(&SettledTask{}).Count(&c).Error; err != nil {
+		return 0, errors.Wrap(err, "failed to count settled task")
+	}
+	return c, nil
+}
+
 func (p *DB) UpsertProjectDevice(projectID *big.Int, address common.Address) error {
 	t := ProjectDevice{
 		ProjectID:     projectID.String(),