diff --git a/internal/flag/internal_flag.go b/internal/flag/internal_flag.go
index 0ea7394bc67..d9b6d35666e 100644
--- a/internal/flag/internal_flag.go
+++ b/internal/flag/internal_flag.go
@@ -27,7 +27,7 @@ type InternalFlag struct {
 	Rules *[]Rule `json:"targeting,omitempty" yaml:"targeting,omitempty" toml:"targeting,omitempty"`
 
 	// BucketingKey defines a source for a dynamic targeting key
-	BucketingKey string `json:"bucketingKey,omitempty" yaml:"bucketingKey,omitempty" toml:"bucketingKey,omitempty"`
+	BucketingKey *string `json:"bucketingKey,omitempty" yaml:"bucketingKey,omitempty" toml:"bucketingKey,omitempty"`
 
 	// DefaultRule is the originalRule applied after checking that any other rules
 	// matched the user.
@@ -80,7 +80,7 @@ func (f *InternalFlag) Value(
 		maps.Copy(evaluationCtx.GetCustom(), flagContext.EvaluationContextEnrichment)
 	}
 
-	key, keyError := flag.GetBucketingKey(evaluationCtx)
+	key, keyError := flag.GetBucketingKeyValue(evaluationCtx)
 
 	if keyError != nil {
 		return flagContext.DefaultSdkValue, ResolutionDetails{
@@ -380,9 +380,22 @@ func (f *InternalFlag) GetVariationValue(name string) interface{} {
 	return nil
 }
 
-func (f *InternalFlag) GetBucketingKey(ctx ffcontext.Context) (string, error) {
-	if f.BucketingKey != "" {
-		value := ctx.GetCustom()[f.BucketingKey]
+// GetBucketingKey return the name of the custom bucketing key if we are using one.
+func (f *InternalFlag) GetBucketingKey() string {
+	if f.BucketingKey == nil {
+		return ""
+	}
+	return *f.BucketingKey
+}
+
+// GetBucketingKeyValue return the value of the bucketing key from the context
+func (f *InternalFlag) GetBucketingKeyValue(ctx ffcontext.Context) (string, error) {
+	if f.BucketingKey != nil {
+		key := f.GetBucketingKey()
+		if key == "" {
+			return ctx.GetKey(), nil
+		}
+		value := ctx.GetCustom()[f.GetBucketingKey()]
 		switch v := value.(type) {
 		case string:
 			return v, nil
@@ -390,7 +403,6 @@ func (f *InternalFlag) GetBucketingKey(ctx ffcontext.Context) (string, error) {
 			return "", fmt.Errorf("invalid bucketing key")
 		}
 	}
-
 	return ctx.GetKey(), nil
 }
 
diff --git a/internal/flag/internal_flag_test.go b/internal/flag/internal_flag_test.go
index e76677e314c..6ab74b0bb7f 100644
--- a/internal/flag/internal_flag_test.go
+++ b/internal/flag/internal_flag_test.go
@@ -1731,7 +1731,7 @@ func TestInternalFlag_ValueWithBucketingKey(t *testing.T) {
 					"variation_B": testconvert.Interface("value_B"),
 					"variation_C": testconvert.Interface("value_C"),
 				},
-				BucketingKey: "teamId",
+				BucketingKey: testconvert.String("teamId"),
 				DefaultRule: &flag.Rule{
 					Percentages: &map[string]float64{
 						"variation_A": 33,
@@ -1758,7 +1758,7 @@ func TestInternalFlag_ValueWithBucketingKey(t *testing.T) {
 			assert.Equal(t, tt.wantForTeamID, got.Variant)
 
 			flagWithoutBucketingKey := tt.flag
-			flagWithoutBucketingKey.BucketingKey = ""
+			flagWithoutBucketingKey.BucketingKey = testconvert.String("")
 			_, got = flagWithoutBucketingKey.Value(tt.args.flagName, tt.args.user, tt.args.flagContext)
 
 			assert.Equal(t, tt.wantForTargetingKey, got.Variant)
@@ -1773,7 +1773,7 @@ func TestInternalFlag_ValueWithBucketingKeyNotFound(t *testing.T) {
 			"variation_B": testconvert.Interface("value_B"),
 			"variation_C": testconvert.Interface("value_C"),
 		},
-		BucketingKey: "teamId",
+		BucketingKey: testconvert.String("teamId"),
 		DefaultRule: &flag.Rule{
 			Percentages: &map[string]float64{
 				"variation_A": 33,
diff --git a/model/dto/dto.go b/model/dto/dto.go
index ff87ce0292f..d1fab169c32 100644
--- a/model/dto/dto.go
+++ b/model/dto/dto.go
@@ -38,7 +38,7 @@ type DTOv1 struct {
 	Rules *[]flag.Rule `json:"targeting,omitempty" yaml:"targeting,omitempty" toml:"targeting,omitempty" jsonschema:"title=targeting,description=List of rule to target a subset of the users based on the evaluation context."` // nolint: lll
 
 	// BucketingKey defines a source for a dynamic targeting key
-	BucketingKey string `json:"bucketingKey,omitempty" yaml:"bucketingKey,omitempty" toml:"bucketingKey,omitempty"`
+	BucketingKey *string `json:"bucketingKey,omitempty" yaml:"bucketingKey,omitempty" toml:"bucketingKey,omitempty"`
 
 	// DefaultRule is the rule applied after checking that any other rules
 	// matched the user.