Request header value does not match

Matches when the value of a specific request header does not match a regular expression.

This condition inspects the value of a specified header sent in the request to determine if it does not match a regular expression. It returns true if the named header contains no values that match the defined pattern.

Configuration

  • Case sensitive: Whether to enable case sensitivity during the name and value comparison. When disabled, the condition performs a case-insensitive match for the header name and evaluates the pattern against all headers sent in the request that match that name.
  • Name: The exact name of the request header to inspect. This field is required and supports a maximum of 50 characters.
  • Pattern: The RE2 regular expression used to evaluate the header’s value. The condition returns true if the pattern does not match the value of the specified header. This field is required and supports a maximum of 255 characters.

Measurement

The condition extracts all values for the specified header name from the incoming request and evaluates them against the configured pattern.

  • Match found: If any instance of the header matches the regular expression, the condition returns false.
  • No match found: If none of the header values match the pattern, the condition returns true.
  • Missing header: If the specified header is absent from the request, the condition returns true.

Last modified March 5, 2026