Is there any fiverr tool that will help team work like a software project with a client's team

[yishakabrham297]

I am a full stack web developer and my new client is looking for a way to collaborate my work with his developer's team on our new ongoing SAAS project. The thing is fiverr does not allow any communications outside fiverr. So he wants to invite me to the 'Slack' teams group and I refused by mentioning that it is not allowed. So is there any way to get around with this?? And can I ask permission from the fiverr to join the slack? since he wants a workplace like collaboration with his developers team.  

[atulcodex]

I think Fiverr don't allow this 😞