What causes "operator must be AND or OR" in SigNoz/signoz?

Use exactly "AND" or "OR" uppercase, or omit the field entirely

operator must be AND or OR

Error message

operator must be AND or OR

What it means

FilterSet.Validate() requires the Operator field to be empty (default) or exactly "AND"/"OR" (case-sensitive). Any other string is rejected.

Source

Thrown at pkg/query-service/model/v3/v3.go:1191

	Items    []FilterItem `json:"items"`
}

func (f *FilterSet) Clone() *FilterSet {
	if f == nil {
		return nil
	}
	return &FilterSet{
		Operator: f.Operator,
		Items:    f.Items,
	}
}

func (f *FilterSet) Validate() error {
	if f == nil {
		return nil
	}
	if f.Operator != "" && f.Operator != "AND" && f.Operator != "OR" {
		return fmt.Errorf("operator must be AND or OR")
	}
	for _, item := range f.Items {
		if err := item.Key.Validate(); err != nil {
			return fmt.Errorf("filter item key is invalid: %w", err)
		}
	}
	return nil
}

// For serializing to and from db
func (f *FilterSet) Scan(src interface{}) error {
	if data, ok := src.([]byte); ok {
		return json.Unmarshal(data, &f)
	}
	return nil
}

func (f *FilterSet) Value() (driver.Value, error) {

View on GitHub (pinned to 5069bf80b0)

Solutions

Use exactly "AND" or "OR" uppercase, or omit the field entirely
Normalize the operator client-side: trim + uppercase + whitelist before sending

Example fix

// before
{"operator":"and","items":[...]}
// after
{"operator":"AND","items":[...]}

Defensive patterns

Strategy: validation

Validate before calling

op := strings.ToUpper(strings.TrimSpace(fs.Operator))
if op != "" && op != "AND" && op != "OR" { return errors.New("operator must be AND or OR") }

Type guard

func isValidFilterOperator(op string) bool { return op == "" || op == "AND" || op == "OR" }

Prevention

Whitelist and normalize operators to uppercase before sending
Omit operator to use the default

When it happens

Trigger: Sending a filter set with "operator":"and" (lowercase), "AND ", "not", or "&&" in a query builder payload.

Common situations: Lowercasing middleware, hand-crafted curl payloads, or client enums that use different tokens (&& / ||).

Related errors

AI-assisted analysis of SigNoz/signoz@5069bf80b0 (2026-08-28). Data as JSON: /api/errors/58464ebbca8912da. Report an issue: GitHub.