Is The Service Serveo.net Safe And Private?

I created a reverse tcp payload for android on port 3333. and forwarded it with serveo. But the main Concern is anyone in the world can listen on this port and get the reverse conn

Solution 1:

Used serveo and ngrok and stuck with ngrok. I believe them when they say it's safe but I also added additional layers of security to my host machine that issues the SSH, by hardening the SSH config and opening up the minimum ports required in iptables. For example I limited inbound SSH traffic only from my local subnet. I did this because while learning about ngrok, I found on the net (forgot where) that there is a chance someone can determine the IP of the host machine.