diff --git a/search_knn.go b/search_knn.go
index 279f35df1..fde086268 100644
--- a/search_knn.go
+++ b/search_knn.go
@@ -90,7 +90,7 @@ type KNNRequest struct {
 
 	// Filter query to use with kNN pre-filtering.
 	// Supports pre-filtering with all existing types of query clauses.
-	FilterQuery query.Query `JSON:"filter,omitempty"`
+	FilterQuery query.Query `json:"filter,omitempty"`
 }
 
 func (r *SearchRequest) AddKNN(field string, vector []float32, k int64, boost float64) {
@@ -129,7 +129,7 @@ func (r *SearchRequest) UnmarshalJSON(input []byte) error {
 		K            int64           `json:"k"`
 		Boost        *query.Boost    `json:"boost,omitempty"`
 		Params       json.RawMessage `json:"params"`
-		FilterQuery  json.RawMessage `JSON:"filter,omitempty"`
+		FilterQuery  json.RawMessage `json:"filter,omitempty"`
 	}
 
 	var temp struct {