Hi @Transvaal lion, have you tried to check on google ? I found that and maybe this could help you and solve your problem? https://firebase.google.com/codelabs/firebase-nextjs#0

Thanks ! yes I've seen this but they set the cookie on the client is that not a problem ?

if think it's not secure

what do you think ?

Mhhh, I'm no expert, but I think it's generally acceptable as long as you're not storing sensitive data.

ok I see

and do you have experience with firebase auth with nextjs ?

Not at all, that's why I sent the firebase link but I think someone more experienced could help you.
I also found this article in this discord server, see if it suits your needs: https://discord.com/channels/752553802359505017/1319649129437331556/1319649129437331556

thanks I'm gonna check this, you help me a lot !

To be honest, I didn't do anything haha, but one of my practices is to see if some people haven't already solved my problem on the discord/forum. Don't hesitate to ask again later, I'm sure people will be able to help you.