diff --git a/internals/coordinator/coordinator_test.go b/internals/coordinator/coordinator_test.go
index 49f0c85..0a3d36f 100644
--- a/internals/coordinator/coordinator_test.go
+++ b/internals/coordinator/coordinator_test.go
@@ -124,7 +124,7 @@ func TestCoordinator(t *testing.T) {
 				ID:   1,
 				Name: "myindex",
 				ElasticsearchOptions: modeler.ElasticsearchOptions{
-					Rollmode:                  "timebased",
+					Rollmode:                  modeler.RollmodeSettings{Type: modeler.RollmodeTimeBased},
 					Rollcron:                  "0 * * * *",
 					EnablePurge:               true,
 					PurgeMaxConcurrentIndices: 30,
@@ -150,7 +150,7 @@ func TestPurge(t *testing.T) {
 	elasticsearchsdk.ReplaceGlobals(elasticsearch.Config{Addresses: viper.GetStringSlice("ELASTICSEARCH_URLS")})
 
 	logicalIndex, err := NewLogicalIndexTimeBased("myrtea", modeler.Model{Name: "myindex", ElasticsearchOptions: modeler.ElasticsearchOptions{
-		Rollmode:                  "timebased",
+		Rollmode:                  modeler.RollmodeSettings{Type: modeler.RollmodeTimeBased},
 		Rollcron:                  "0 * * * *",
 		EnablePurge:               true,
 		PurgeMaxConcurrentIndices: 30,
diff --git a/internals/coordinator/instance.go b/internals/coordinator/instance.go
index 9c3174d..7d46702 100644
--- a/internals/coordinator/instance.go
+++ b/internals/coordinator/instance.go
@@ -40,10 +40,10 @@ func InitInstance(instanceName string, models map[int64]modeler.Model) error {
 	for _, model := range models {
 		var err error
 		var logicalIndex LogicalIndex
-		switch model.ElasticsearchOptions.Rollmode {
-		case "cron":
+		switch model.ElasticsearchOptions.Rollmode.Type {
+		case modeler.RollmodeCron:
 			logicalIndex, err = NewLogicalIndexCron(instance.Name, model)
-		case "timebased":
+		case modeler.RollmodeTimeBased:
 			logicalIndex, err = NewLogicalIndexTimeBased(instance.Name, model)
 		}
 		if err != nil {
diff --git a/internals/coordinator/logicalindex_cron.go b/internals/coordinator/logicalindex_cron.go
index dbc7531..b7695bd 100644
--- a/internals/coordinator/logicalindex_cron.go
+++ b/internals/coordinator/logicalindex_cron.go
@@ -36,7 +36,7 @@ func NewLogicalIndexCron(instanceName string, model modeler.Model) (*LogicalInde
 
 	zap.L().Info("Initialize logicalIndex (LogicalIndexCron)", zap.String("name", logicalIndexName), zap.String("model", model.Name), zap.Any("options", model.ElasticsearchOptions))
 
-	if model.ElasticsearchOptions.Rollmode != "cron" {
+	if model.ElasticsearchOptions.Rollmode.Type != modeler.RollmodeCron {
 		return nil, errors.New("invalid rollmode for this logicalIndex type")
 	}
 
diff --git a/internals/coordinator/logicalindex_timebased.go b/internals/coordinator/logicalindex_timebased.go
index aea1231..bee6ea3 100644
--- a/internals/coordinator/logicalindex_timebased.go
+++ b/internals/coordinator/logicalindex_timebased.go
@@ -31,7 +31,7 @@ func NewLogicalIndexTimeBased(instanceName string, model modeler.Model) (*Logica
 
 	zap.L().Info("Initialize logicalIndex (LogicalIndexTimeBased)", zap.String("name", logicalIndexName), zap.String("model", model.Name), zap.Any("options", model.ElasticsearchOptions))
 
-	if model.ElasticsearchOptions.Rollmode != "timebased" {
+	if model.ElasticsearchOptions.Rollmode.Type != modeler.RollmodeTimeBased {
 		return nil, errors.New("invalid rollmode for this logicalIndex type")
 	}
 
@@ -59,6 +59,7 @@ func NewLogicalIndexTimeBased(instanceName string, model modeler.Model) (*Logica
 	}
 
 	logicalIndex.FetchIndices()
+	zap.L().Info("LogicalIndex initialized", zap.String("logicalIndex", logicalIndex.Name))
 
 	c := cron.New()
 	_, err = c.AddFunc("*/30 * * * *", logicalIndex.FetchIndices)
@@ -90,8 +91,18 @@ func (logicalIndex *LogicalIndexTimeBased) purge() {
 		return
 	}
 
-	tsStart := time.Now().Add(time.Duration(logicalIndex.Model.ElasticsearchOptions.PurgeMaxConcurrentIndices) * -1 * 24 * time.Hour)
-	indexStart := fmt.Sprintf("%s-%s", logicalIndex.Name, tsStart.Format("2006-01-02"))
+	var indexStart string
+	var tsStart time.Time
+
+	if logicalIndex.Model.ElasticsearchOptions.Rollmode.Timebased.Interval == modeler.Daily {
+		// Daily mode: calculation based on a number of days
+		tsStart = time.Now().Add(time.Duration(logicalIndex.Model.ElasticsearchOptions.PurgeMaxConcurrentIndices) * -1 * 24 * time.Hour)
+		indexStart = fmt.Sprintf("%s-%s", logicalIndex.Name, tsStart.Format("2006-01-02"))
+	} else if logicalIndex.Model.ElasticsearchOptions.Rollmode.Timebased.Interval == modeler.Monthly {
+		// Monthly mode: calculation based on a number of months
+		tsStart = time.Now().AddDate(0, -logicalIndex.Model.ElasticsearchOptions.PurgeMaxConcurrentIndices, 0)
+		indexStart = fmt.Sprintf("%s-%s", logicalIndex.Name, tsStart.Format("2006-01"))
+	}
 
 	allIndices := logicalIndex.GetAllIndices()
 	indices := make([]string, 0)
@@ -168,9 +179,18 @@ func (logicalIndex *LogicalIndexTimeBased) GetAllIndices() []string {
 }
 
 func (logicalIndex *LogicalIndexTimeBased) FindIndices(t time.Time, depthDays int64) ([]string, error) {
-	tsStart := t.Add(time.Duration(depthDays) * -1 * 24 * time.Hour)
-	indexEnd := fmt.Sprintf("%s-%s", logicalIndex.Name, t.Format("2006-01-02"))
-	indexStart := fmt.Sprintf("%s-%s", logicalIndex.Name, tsStart.Format("2006-01-02"))
+	var indexStart, indexEnd string
+
+	if logicalIndex.Model.ElasticsearchOptions.Rollmode.Timebased.Interval == modeler.Daily {
+		tsStart := t.Add(time.Duration(-depthDays) * 24 * time.Hour)
+		indexEnd = fmt.Sprintf("%s-%s", logicalIndex.Name, t.Format("2006-01-02"))
+		indexStart = fmt.Sprintf("%s-%s", logicalIndex.Name, tsStart.Format("2006-01-02"))
+	} else if logicalIndex.Model.ElasticsearchOptions.Rollmode.Timebased.Interval == modeler.Monthly {
+		// For a monthly interval, we calculate the starting point in months
+		tsStart := t.AddDate(0, int(-depthDays/30), 0)
+		indexEnd = fmt.Sprintf("%s-%s", logicalIndex.Name, t.Format("2006-01"))
+		indexStart = fmt.Sprintf("%s-%s", logicalIndex.Name, tsStart.Format("2006-01"))
+	}
 
 	indices := make([]string, 0)
 	logicalIndex.mu.RLock()