Variables in Custom Caller

Hi @Wojciech_Gilarski
Welcome to the community :wave:
If I understood you rightly, you are looking for a way to add [userId] as a parameter apart from [number] ?
At the moment, you can only use [number] as described in Callto Syntax: Make VOIP calls from Pipedrive - Knowledge Base

However, you can also build a fully custom one as described in Building / Customising Click-to-call functionality