Variable issue with iRule generated by IAPP

have you tried changing the delimiter type to single quotes? eg proc create_iRule { irule_name } { set irule_buffer [string trim '{ when HTTP_REQUEST { set var 0 if { [string tolower [HTTP::path]] contains "test" } { set var 1 } } when HTTP_RESPONSE { if { $var == 1 } { HTTP::header insert "Connection" "Close" } unset var } }'] If not, it may be because you haven't escaped the marks at the end of test : contains \"test" }