What causes "Invalid matcher type: %s" in projectdiscovery/nuclei?

Use one of: status, size, word, regex, binary, dsl, xpath

Invalid matcher type: %s

Error message

Invalid matcher type: %s

What it means

Raised by toMatcherTypes when a template matcher's type field, after TrimSpace + ToLower, matches none of MatcherTypes. Supported matcher types are: status, size, word, regex, binary, dsl, xpath (matchers_types.go:34-42). MatcherTypeHolder.UnmarshalYAML propagates the error, aborting template compilation at load time.

Source

Thrown at pkg/operators/matchers/matchers_types.go:65

}

// GetSupportedMatcherTypes returns list of supported types
func GetSupportedMatcherTypes() []MatcherType {
	var result []MatcherType
	for index := MatcherType(1); index < limit; index++ {
		result = append(result, index)
	}
	return result
}

func toMatcherTypes(valueToMap string) (MatcherType, error) {
	normalizedValue := normalizeValue(valueToMap)
	for key, currentValue := range MatcherTypes {
		if normalizedValue == currentValue {
			return key, nil
		}
	}
	return -1, errors.New("Invalid matcher type: " + valueToMap)
}

func normalizeValue(value string) string {
	return strings.TrimSpace(strings.ToLower(value))
}

func (t MatcherType) String() string {
	return MatcherTypes[t]
}

// MatcherTypeHolder is used to hold internal type of the matcher
type MatcherTypeHolder struct {
	MatcherType MatcherType `mapping:"true"`
}

func (t MatcherTypeHolder) String() string {
	return t.MatcherType.String()
}

View on GitHub (pinned to 265b3a3dec)

Solutions

Use one of: status, size, word, regex, binary, dsl, xpath
Match headers with type: word plus part: header; match body text with type: word plus part: body
Run nuclei -validate on the template before scanning

Example fix

# before
matchers:
  - type: header
    header:
      - 'X-Powered-By: Express'
# after
matchers:
  - type: word
    part: header
    words:
      - 'X-Powered-By: Express'

Defensive patterns

Strategy: validation

Validate before calling

var validMatcherTypes = map[string]bool{"status": true, "size": true, "word": true, "regex": true, "binary": true, "dsl": true, "xpath": true}
func matcherTypeOK(s string) bool { return validMatcherTypes[strings.ToLower(strings.TrimSpace(s))] }

Prevention

Lint templates for the seven matcher types
Remember 'part: header/body' composes with word/regex instead of dedicated types

When it happens

Trigger: A matcher with type: header, type: body, or type: status-code; any value outside the seven-word enum.

Common situations: Intuitive but unsupported names ('header', 'body', 'favicon'); templates ported from other tools; condition words ('and', 'or') pasted into the type slot.

Related errors

AI-assisted analysis of projectdiscovery/nuclei@265b3a3dec (2026-08-15). Data as JSON: /api/errors/1ccadfec0bd2d30e. Report an issue: GitHub.