devchat-p2p 1.0.0

A professional, globally-connected, E2E encrypted terminal chat for developers.

DevChat P2P

A terminal chat application for developers who work in the command line

A globally connected, end-to-end encrypted terminal chat application.

Connect with any developer directly from your terminal. No accounts, no servers to manage, and no data collection. Just encrypted communication between two machines.

Built by Soumyadip Ghosh

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Why DevChat

DevChat solves a few recurring problems for developers who prefer the terminal.

Problem	How DevChat handles it
Sharing a code snippet with a remote colleague	Markdown rendering with syntax highlighting
Not wanting to route private conversations through third-party chat apps	End-to-end Fernet encryption, with keys held only on your machines
Chat apps cluttering project folders with config files	All data stays in ~/.devchat/, leaving your workspace untouched
Firewalls and NATs blocking direct connections	An MQTT relay that works across most networks
Sending files securely	Chunked, encrypted file transfer built in

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Features

• Global connectivity through an MQTT relay over TLS (port 8883) that traverses most NAT and firewall setups
• End-to-end encryption using Fernet symmetric encryption, with the shared key kept on your terminal
• Encrypted file transfer with chunked delivery and progress tracking
• Rich terminal UI built with Textual, including Markdown rendering and syntax highlighting
• Message delivery receipts that track SENDING → DELIVERED → READ status in real time
• Live typing indicators that show when your peer is typing, debounced to avoid noise
• Persistent local history stored in ~/.devchat/history.db using SQLite with WAL mode
• CSV export of your full chat history with a single command
• Latency ping to measure connection round-trip time in milliseconds
• Clean workspace with no files written to your project directories
• Automatic reconnection that handles disconnects gracefully
• Clipboard integration that copies auth tokens when a room is created

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Installation

From PyPI (recommended)

pip install devchat-p2p

From source

# 1. Clone the repository
git clone https://github.com/dev-soumyadip/devchat-p2p.git
cd devchat-p2p

# 2. Install in editable mode
pip install -e .

Verify the installation

devchat --help

Expected output:

usage: devchat [-h] {config,history,export,host,join} ...

DevChat Professional Interface

positional arguments:
  {config,history,export,host,join}
    config              Set Global Identity
    history             Print local persistent chat history
    export              Export history to CSV in downloads folder
    host                Initialize a secure global room
    join                Connect to an existing room

options:
  -h, --help            show this help message and exit

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Quick start

Step 1: Set your identity (optional but recommended)

devchat config --username "yourname" --email "[e-mail]"

If you skip this step, you will appear as guest_xxxx@devchat.

Step 2: Host a secure room

devchat host

This creates a unique encrypted room, generates a secure auth token, and copies that token to your clipboard (or prints it to the terminal). Share the token with the person you want to chat with. If you lose it, run /copytoken inside the chat to copy it again.

Step 3: Join a room from the other machine

devchat join <AUTH_TOKEN>

Paste the token you received and you are connected.

Step 4: Start chatting

• Type a message and press Enter to send it
• Use Markdown syntax, which renders inline:
  • `inline code`, bold, italic
  • Code blocks with syntax highlighting (```python)
• Press Ctrl+Q to quit

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Command reference

CLI commands

Command	Description	Example
devchat host	Create a new encrypted chat room	devchat host
devchat join <token>	Join an existing room using an auth token	devchat join aBcD3F...
devchat config	Set your global identity	devchat config --username "alice"
devchat history	Print all saved messages to the terminal	devchat history
devchat export	Export full chat history as CSV	devchat export

Config options

Flag	Description	Example
--username	Set your display name	devchat config --username "alice"
--email	Set your email (stored locally)	devchat config --email "[e-mail]"
--pubkey	Store a public key reference	devchat config --pubkey "ssh-rsa..."

In-chat commands

Command	Description
/help	Show all available in-chat commands
/file <path>	Send a file, with live autocomplete
/send <path>	Alias for /file
/copytoken	Copy the auth token to the clipboard again
/ping	Measure round-trip connection latency in ms
/status	Show your identity and current room ID
/export	Export chat history to a CSV file
/clear	Clear the terminal chat display
/quit	Exit the application

File autocomplete: when you type /file followed by any letters, DevChat shows real-time file suggestions from your current directory. It supports fuzzy matching, so typing main will find src/main.py.

Keyboard shortcuts

Shortcut	Action
Enter	Send message
Ctrl+Q	Quit the application

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File transfer

DevChat can send files of any type over the encrypted channel.

Sending a file

On Windows:

/file C:\Users\you\Documents\report.pdf

On macOS or Linux:

/send ~/Documents/report.pdf

How it works

1. The file is split into 32KB chunks
2. Each chunk is Base64 encoded, then Fernet encrypted, then sent over TLS MQTT
3. The receiver sees a real-time progress bar
4. Chunks are reassembled and verified on arrival
5. The completed file is saved to ~/.devchat/downloads/

Security notes

• Filenames are sanitized, which blocks path traversal attempts
• Chunk integrity is verified before assembly
• Data passes through Fernet encryption, then TLS, then MQTT

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Data storage and privacy

All persistent data is stored in your home directory. Nothing is written to your project folders.

~/.devchat/
├── config.json        # Your identity (username, email)
├── history.db         # SQLite message history (WAL mode)
├── devchat.log        # Rotating application logs (5MB x 3)
└── downloads/         # Received files and CSV exports
    ├── report.pdf
    └── export_20260624_211500.csv

Item	Location	Purpose
Config	~/.devchat/config.json	Stores username, email, and public key reference
Database	~/.devchat/history.db	All messages with timestamps, status, and sender
Logs	~/.devchat/devchat.log	Rotating debug and error logs
Downloads	~/.devchat/downloads/	Received files and CSV exports

Windows path: C:\Users\<you>\.devchat\

macOS and Linux path: /home/<you>/.devchat/ or /Users/<you>/.devchat/

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Architecture overview

┌──────────────┐          TLS (8883)          ┌──────────────┐
│   DevChat A   │◄──── MQTT Broker ────►│   DevChat B   │
│   (Host)      │    broker.hivemq.com        │   (Joiner)   │
└──────┬────────┘                              └──────┬────────┘
       │                                              │
   Fernet E2E                                    Fernet E2E
   Encryption                                    Decryption
       │                                              │
   ┌───▼────┐                                   ┌─────▼─────┐
   │ SQLite  │ ~/.devchat/history.db             │  SQLite   │
   │  (WAL)  │                                   │  (WAL)    │
   └─────────┘                                   └───────────┘

Design decisions

Layer	Technology	Reasoning
Transport	MQTT over TLS	Traverses NAT and firewalls, and works behind many corporate proxies
Broker	HiveMQ (public)	Globally available with a reliable free tier
Encryption	Fernet (AES-128-CBC with HMAC)	Symmetric and fast, with the key shared through the token
UI framework	Textual (Python)	Rich terminal UI with Markdown and syntax highlighting
Storage	SQLite with WAL	Thread-safe and zero-config, with no external database
Token	Base64(room_id:fernet_key)	A single string that carries both routing and encryption info

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System requirements

Requirement	Minimum
Python	3.9 or higher
OS	Windows 10+, macOS 10.15+, or any modern Linux distribution
Network	Internet access with outbound TCP port 8883 for MQTT over TLS
Terminal	Any modern terminal, such as Windows Terminal, iTerm2, or GNOME Terminal

Dependencies (installed automatically)

Package	Purpose
textual	Terminal UI framework
rich	Markdown rendering and syntax highlighting
paho-mqtt	MQTT client for global connectivity
cryptography	Fernet end-to-end encryption
pyperclip	Clipboard integration (optional)

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Troubleshooting

Connection rejected or unable to connect

• Check your internet connection
• Confirm that outbound TCP port 8883 is open, since some corporate firewalls block it
• Try a different network, such as a mobile hotspot, to isolate the issue

Token error when joining

• Make sure you copied the entire token string
• Tokens are single use per room, so a new token is generated if the host restarts
• Avoid adding extra spaces or newlines when pasting

No clipboard support

• On headless Linux servers, pyperclip may not work, so the token is printed to the terminal instead
• On Linux, install xclip or xsel, for example sudo apt install xclip

Messages not appearing

• Check ~/.devchat/devchat.log for error details
• Confirm that both peers are using the same token
• Run /ping, and if you receive a pong response, the connection is working

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Usage examples

Quick chat between two developers

Developer A (host):

$ devchat config --username "alice"
[*] Configuration saved to ~/.devchat/config.json

$ devchat host
# UI launches, token is copied to clipboard
# Share the token with Developer B

Developer B (joiner):

$ devchat config --username "bob"
$ devchat join "dGhpcyBpcyBhIHNhbXBsZSB0b2tlbg=="
# UI launches, connected to Alice's room

Send a file

# Inside the chat UI, type:
/file ./my_script.py

# Output:
# [*] INITIATING TRANSFER: my_script.py
# [*] UPLOADING my_script.py ... 100%
# [*] UPLOAD COMPLETE: my_script.py

Export chat history

# From the CLI:
$ devchat export
[*] History successfully exported to ~/.devchat/downloads/export_20260624_211500.csv

# Or from inside the chat UI:
/export

Check connection quality

# Inside the chat UI:
/ping

# Output:
# [*] PONG received: 42.37ms latency

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Roadmap

• Multi-room support with tabs
• Message reactions (emoji)
• Code snippet mode (/code python)
• Room persistence and rejoin
• User presence (online, offline, idle)
• WebSocket transport fallback (port 443)
• Full-text message search (/search)
• Message editing and deletion
• Desktop notifications
• Self-hosted broker option
• Plugin and hook system

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License

This project is licensed under the MIT License. See the LICENSE file for details.

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Author

Soumyadip Ghosh

GitHub

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If DevChat is useful to you, a star on the repository is appreciated.

Built with Python, Fernet, MQTT, and Textual.