@miconda i need the first line, to, from and callid. I'll take a look in tm for the lightweight parsing. I also got one question: The case when you want to use the duplicate_uri(modparam) and not the destination uri(siptrace parameter) is not covered. I don't exactly know what's the best practice in kamailio to pass a null parameter to a function. I tried with "$null", I get a NULL pvar in code but I didn't see this implemented in other modules(or maybe I didn't look well enough).