Justniffer is described as 'justniffer is a TCP sniffer. It reassembles and reorders packets and displays the tcp flow in a customizable way. It can log network traffic in web server log format. It can also log network services performances and extract http content' and is an app in the Network & Admin category. There are six alternatives to Justniffer for a variety of platforms, including Android, BSD, Mac, Windows and Linux. The best alternative is Wireshark, which is both free and Open Source. Other great apps like Justniffer are tcpdump (Free, Open Source), PCAPdroid (Free, Open Source), HttpCanary (Freemium) and Appknox (Paid).
Wireshark is the world's foremost network protocol analyzer. It lets you capture and interactively browse the traffic running on a computer network. It is the de facto (and often de jure) standard across many industries and educational institutions.
tcpdump is a common packet analyzer that runs under the command line. It allows the user to intercept and display TCP/IP and other packets being transmitted or received over a network to which the computer is attached.
PCAPdroid is an android app to capture the phone traffic and analyze it remotely (e.g. via Wireshark). The traffic can be easily downloaded from a remote device thanks to the integrated HTTP server, or streamed to a remote UDP receiver.
HttpCanary supports packets capture and injection. With this app, you can test your mobile Rest APIs very very easy. Besides, HttpCanary provides multiple view browsers, such as raw viewer, hex viewer, preview viewer and so on.