> <@freenode_yyug[m]:matrix.org> freenode_anonmon777[m]: Here are a few answers:
> Sorry, I'm not aware of good PHP/Node libraries but am sure there will be one.
> 
> Janus attack is still possible. There are several approaches to preventing it but AFAIK decisions have not been made yet: https://www.reddit.com/r/Monero/comments/kswcgh/is_janus_attack_still_possible/
> 
> Janus attack is quite edge case and expensive for the attacker usually AFAIK.
> 
> Most merchants will use subaddresses rather than integrated addresses, I think. (certainly in my experience).
> 
> There isn't anywhere to put a "private message", really. Do not use `tx_extra`, it is frowned upon because it bloats the blockchain. Also tx_extra may well be removed in a future monero upgrade. Bear in mind there are man, many merchants who integrate Monero without needing any private message stored in the transaction.

Sure. Thanks for you answered. I want to build something totally new. I don't need the ´´´tx_extra´´´ for the merchant thing.