Tailcat-Box

Project Overview

Tailcat Box is a desktop peer-to-peer tool for developers, IT helpers, and small teams, solving the problem of linking two computers across different networks. Built on Tailscale Tailcat, connections are brokered through public DERP relays and switch to a direct path when the network allows, so neither side needs a public IP, router changes, or an account. Open the app, swap a short tc… address or pickup code, and one window covers chat, file transfer, reaching each other's services, and a remote shell, with WireGuard encryption underneath.

No VPN to set up and no cloud drive in between, just a private channel between two machines.

Item	Value
Platform	Windows, macOS, Linux (x64 / ARM64)
Stack	Go + Wails + React
Connection	Tailscale Tailcat (DERP relay + direct path)
License	PolyForm Noncommercial 1.0.0
UI languages	Simplified Chinese, English, light and dark themes

Key Features

• Room chat: one-to-one rooms with text, files, and voice notes, plus voice/video calls and screen sharing
• Mew Share transfers: recipients download straight from your computer with a pickup code or QR code, no third-party storage
• Tunnel forwarding: publish a local or LAN device's TCP port as a Tailcat address, the peer adds a Local forward to reach it
• Built-in SSH: an independent shell served by Tailcat, off by default and limited to saved devices and current chat peers
• Tray resident: rooms, shares, and tunnels keep working when the window closes
• Multi-room: keep several rooms open and switch freely, shared screens open full-resolution in their own window

File Sharing & Tunnel

• Multi-recipient codes: one pickup code serves several people, up to 10 downloading at once with the rest queued, download limits and expiry configurable
• Parallel shares: run several shares at the same time, each with its own expiry
• No copying for big files: large shares are served from their original location and resume with the same code after restart
• Port mapping syntax: publish another LAN host with a mapping like 8080:192.168.1.10:80, one address serving many peers at once
• Stable address: with a saved key the address stays the same across restarts

Target Audience

• Developers reaching a home NAS or office intranet from anywhere
• Engineers demoing a local dev server to colleagues
• Technical users remotely fixing a family member's computer
• Privacy-minded people who keep files off cloud drives

Quick Start

1. Install Tailcat Box on both computers, packages per platform in Releases
2. Create a room on one side and send its tc… address or QR code, the other pastes or scans to connect
3. To send files, drop them into Mew Share and hand over the pickup code, the recipient enters it on the Download page
4. To expose a service, add a Port serve mapping in Tunnel (say 8080), the peer adds a matching Local forward

System Requirements

Item	Requirement
Windows	x64 / ARM64, installer or portable
macOS	Apple silicon or Intel, DMG
Linux	x64 / ARM64, deb or tar.gz, glibc 2.39+, full package for calls

Notes

• Addresses are keys: anyone holding a room address, Tunnel address, or pickup code can connect, stop them when done
• Noncommercial license: PolyForm Noncommercial 1.0.0, commercial use needs a separate license
• Unsigned builds: Windows SmartScreen and macOS Gatekeeper ask for confirmation on first launch
• Build requirements: Go 1.27.1+, Node.js 20.19+, and Wails CLI v2.16.0 for source builds