diff --git a/backend/internal/handler/gemini_v1beta_handler.go b/backend/internal/handler/gemini_v1beta_handler.go
index 6b8cc482..d200c17c 100644
--- a/backend/internal/handler/gemini_v1beta_handler.go
+++ b/backend/internal/handler/gemini_v1beta_handler.go
@@ -121,7 +121,7 @@ func (h *GatewayHandler) GeminiV1BetaGetModel(c *gin.Context) {
 		googleError(c, http.StatusBadGateway, err.Error())
 		return
 	}
-	if shouldFallbackGeminiModels(res) {
+	if shouldFallbackGeminiModel(modelName, res) {
 		c.JSON(http.StatusOK, gemini.FallbackModel(modelName))
 		return
 	}
diff --git a/backend/internal/pkg/websearch/brave.go b/backend/internal/pkg/websearch/brave.go
index 5620ca8d..707e7029 100644
--- a/backend/internal/pkg/websearch/brave.go
+++ b/backend/internal/pkg/websearch/brave.go
@@ -62,7 +62,7 @@ func (b *BraveProvider) Search(ctx context.Context, req SearchRequest) (*SearchR
 	if err != nil {
 		return nil, fmt.Errorf("brave: request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	body, err := io.ReadAll(io.LimitReader(resp.Body, maxResponseSize))
 	if err != nil {
diff --git a/backend/internal/pkg/websearch/manager_test.go b/backend/internal/pkg/websearch/manager_test.go
index cbcf1b76..a4413417 100644
--- a/backend/internal/pkg/websearch/manager_test.go
+++ b/backend/internal/pkg/websearch/manager_test.go
@@ -50,7 +50,7 @@ func TestManager_SearchWithBestProvider_UsesFirstAvailable(t *testing.T) {
 	srvBrave := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		resp := braveResponse{}
 		resp.Web.Results = []braveResult{{URL: "https://brave.com", Title: "Brave", Description: "from brave"}}
-		json.NewEncoder(w).Encode(resp)
+		_ = json.NewEncoder(w).Encode(resp)
 	}))
 	defer srvBrave.Close()
 
@@ -77,7 +77,7 @@ func TestManager_SearchWithBestProvider_NilRedis(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		resp := braveResponse{}
 		resp.Web.Results = []braveResult{{URL: "https://test.com", Title: "Test", Description: "result"}}
-		json.NewEncoder(w).Encode(resp)
+		_ = json.NewEncoder(w).Encode(resp)
 	}))
 	defer srv.Close()
 
diff --git a/backend/internal/service/payment_config_service.go b/backend/internal/service/payment_config_service.go
index 6d470342..9042c3ab 100644
--- a/backend/internal/service/payment_config_service.go
+++ b/backend/internal/service/payment_config_service.go
@@ -105,26 +105,26 @@ type MethodLimitsResponse struct {
 }
 
 type CreateProviderInstanceRequest struct {
-	ProviderKey     string            `json:"provider_key"`
-	Name            string            `json:"name"`
-	Config          map[string]string `json:"config"`
-	SupportedTypes  []string          `json:"supported_types"`
-	Enabled         bool              `json:"enabled"`
-	PaymentMode     string            `json:"payment_mode"`
-	SortOrder       int               `json:"sort_order"`
-	Limits          string            `json:"limits"`
-	RefundEnabled   bool              `json:"refund_enabled"`
+	ProviderKey    string            `json:"provider_key"`
+	Name           string            `json:"name"`
+	Config         map[string]string `json:"config"`
+	SupportedTypes []string          `json:"supported_types"`
+	Enabled        bool              `json:"enabled"`
+	PaymentMode    string            `json:"payment_mode"`
+	SortOrder      int               `json:"sort_order"`
+	Limits         string            `json:"limits"`
+	RefundEnabled  bool              `json:"refund_enabled"`
 }
 
 type UpdateProviderInstanceRequest struct {
-	Name            *string           `json:"name"`
-	Config          map[string]string `json:"config"`
-	SupportedTypes  []string          `json:"supported_types"`
-	Enabled         *bool             `json:"enabled"`
-	PaymentMode     *string           `json:"payment_mode"`
-	SortOrder       *int              `json:"sort_order"`
-	Limits          *string           `json:"limits"`
-	RefundEnabled   *bool             `json:"refund_enabled"`
+	Name           *string           `json:"name"`
+	Config         map[string]string `json:"config"`
+	SupportedTypes []string          `json:"supported_types"`
+	Enabled        *bool             `json:"enabled"`
+	PaymentMode    *string           `json:"payment_mode"`
+	SortOrder      *int              `json:"sort_order"`
+	Limits         *string           `json:"limits"`
+	RefundEnabled  *bool             `json:"refund_enabled"`
 }
 type CreatePlanRequest struct {
 	GroupID       int64    `json:"group_id"`