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NanoChat is a peer-to-peer, end-to-end encrypted and discoverable chat application that can be used inside command line. It is totally server-less and every peer can discover other peers in the same subnet without having the network address of them in advance.

It can be compiled and works on both Linux and OSX system platforms.

How to use

Call nanochat with desired flags. In order to see the list of available flags, use --help as follows:

NanoChat help
Avaliable flags:
    Help:          -h --help
    Host IP:       -H --host {host IP}
    Broadcast IP:  -B --broadcast {broadcast IP}
    RPC Port:      -P --port {port}
    Discoverable:  -d --discoverable
    Secure:        -s --secure
  • --host {host IP} flag is used to specify the network interface IP which you want to use. By default it is selected by NanoChat.
  • --broadcast {broadcast IP} flag is used to specify the network interface broadcast IP which you want to use. By default it is selected by NanoChat.
  • --port flag is used to specify the RPC port which is listening to answer chat requests after creating the requested chat room. Its default value is 1991.
  • --discoverable flag is used to let NanoChat to be disovered by other peers, otherwise it doesn't answer to discovery packet and remains hidden from others.
  • --secure flag is used to make NanoChat secure for end to end message encryption with asymmetric/public-key cryptography.

In order to see available commands inside NanoChat use /help command as follows:

$ nanochat --discoverable
NanoChat shell was started.
>> /help
Available commands:
  /help                    prints this text
  /probe                   find online peers
  /list peers              list online peers
  /list rooms              list availabe rooms
  /connect {host} {port}   connect to remote client
  /attach {room}           attach to room
  /quit                    quit nanochat console
>> ...
  • /probe command discovers the subnet for other online NanoChat peers.
  • /list peers command list discovered online peers' host and port address.
  • /list rooms command list available rooms.
  • /connect {host} {port} command connects you to other peers.
  • /attach {room} command is used to enter to a created room by other peers.
  • /quit command closes the NanoChat console.


NanoChat uses GNU Autotools. So you need to have them installed in your system. Also it needs GCC or Clang, GNU Make and GNU Readline library. Other dependencies are included in the NanoChat/lib directory and will be compiled and linked with autotools automatically. So there is no need to get and build it manually.

Debian dependencies:

$ apt-get install gcc make automake autoconf libreadline-dev

Fedora dependencies:

$ yum install gcc make automake autoconf libreadline-devel

OSX dependencies:

$ port install gcc make automake autoconf readline

After making sure that your system has required dependencies, clone the repo and follow installation steps:

$ git clone
$ cd NanoChat
$ autoreconf -i
$ ./configure
$ make && make install
|            NanoChat was successfully installed 
| NanoChat was installed in /usr/local/bin directory. 
| Just type 'nanochat --help' there to get started.

Now nanochat executable file is accessible in the path of your shell.

How it works

My main purpose for writing NanoChat is learning things, so I think it is good to know for you how it works and what tools and protocols it uses.

  • For discovering other online peers in the same subnet it uses raw UDP broadcasting.
  • For inter-node communication it uses some libnanomsg scalibility protocols, for instance REQREP protocol for RPC and PAIR for one to one chat.
  • For user's input/output multiplexing it uses select POSIX-compliant syscall.
  • For storing user's information it uses libvedis embedded datastore engine.
  • For line-editing and history capabilities of commands it uses libreadline.
  • For end to end encryption it uses libsodium public-key cryptography.
  • For message serialization it uses libparson which is a JSON parser.
  • For encoding and decoding encrypted messages before sending over wire it uses base64 codec.


Comments, contributions and patches are greatly appreciated.


The MIT License (MIT).


A P2P, E2E encrypted and discoverable chat application on top of nanomsg library






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